[MC][NFC] Drop unused MCDecodedPseudoProbeInlineTree::ChildrenToProcess

[aaupov]

The usage was removed in 3f97016.

Results in a slight peak RSS reduction in
perf2bolt --profile-use-pseudo-probes from 17.24 to 16.85 GiB.

[llvm-ci]

LLVM Buildbot has detected a new failure on builder llvm-clang-aarch64-darwin running on doug-worker-5 while building llvm at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/190/builds/2682

Here is the relevant piece of the build log for the reference:

Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'Clang Tools :: clang-doc/basic-project.test' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
Emiting docs in html format.
Mapping decls...
Collecting infos...
Reducing 5 infos...
Generating docs...
Generating assets for docs...

--
Command Output (stderr):
--
RUN: at line 1: rm -rf /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-doc/Output/basic-project.test.tmp && mkdir -p /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-doc/Output/basic-project.test.tmp/docs /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-doc/Output/basic-project.test.tmp/build
+ rm -rf /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-doc/Output/basic-project.test.tmp
+ mkdir -p /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-doc/Output/basic-project.test.tmp/docs /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-doc/Output/basic-project.test.tmp/build
RUN: at line 2: sed 's|$test_dir|/Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang-tools-extra/test/clang-doc|g' /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang-tools-extra/test/clang-doc/Inputs/basic-project/database_template.json > /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-doc/Output/basic-project.test.tmp/build/compile_commands.json
+ sed 's|$test_dir|/Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang-tools-extra/test/clang-doc|g' /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang-tools-extra/test/clang-doc/Inputs/basic-project/database_template.json
RUN: at line 3: clang-doc --format=html --output=/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-doc/Output/basic-project.test.tmp/docs --executor=all-TUs /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-doc/Output/basic-project.test.tmp/build/compile_commands.json
+ clang-doc --format=html --output=/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-doc/Output/basic-project.test.tmp/docs --executor=all-TUs /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-doc/Output/basic-project.test.tmp/build/compile_commands.json
[1/3] Processing file /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang-tools-extra/test/clang-doc/Inputs/basic-project/src/Rectangle.cpp
[2/3] Processing file /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang-tools-extra/test/clang-doc/Inputs/basic-project/src/Circle.cpp
[3/3] Processing file /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang-tools-extra/test/clang-doc/Inputs/basic-project/src/Calculator.cpp
RUN: at line 4: FileCheck /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang-tools-extra/test/clang-doc/basic-project.test -input-file=/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-doc/Output/basic-project.test.tmp/docs/index_json.js -check-prefix=JSON-INDEX
+ FileCheck /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang-tools-extra/test/clang-doc/basic-project.test -input-file=/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-doc/Output/basic-project.test.tmp/docs/index_json.js -check-prefix=JSON-INDEX
RUN: at line 5: FileCheck /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang-tools-extra/test/clang-doc/basic-project.test -input-file=/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-doc/Output/basic-project.test.tmp/docs/GlobalNamespace/Shape.html -check-prefix=HTML-SHAPE
+ FileCheck /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang-tools-extra/test/clang-doc/basic-project.test -input-file=/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-doc/Output/basic-project.test.tmp/docs/GlobalNamespace/Shape.html -check-prefix=HTML-SHAPE
�[1m/Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang-tools-extra/test/clang-doc/basic-project.test:64:16: �[0m�[0;1;31merror: �[0m�[1mHTML-SHAPE: expected string not found in input
�[0m// HTML-SHAPE: <h3 id="{{([0-9A-F]{40})}}">area</h3>
�[0;1;32m               ^
�[0m�[1m/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-doc/Output/basic-project.test.tmp/docs/GlobalNamespace/Shape.html:27:53: �[0m�[0;1;30mnote: �[0m�[1mscanning from here
�[0m <p>Defined at line 13 of file ./include/Shape.h</p>
�[0;1;32m                                                    ^
�[0m�[1m/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-doc/Output/basic-project.test.tmp/docs/GlobalNamespace/Shape.html:47:41: �[0m�[0;1;30mnote: �[0m�[1mpossible intended match here
�[0m <a href="#12896F9255F880ECD4A6482CCFA58B238FA2CC49">area</a>
�[0;1;32m                                        ^
�[0m
Input file: /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-doc/Output/basic-project.test.tmp/docs/GlobalNamespace/Shape.html
Check file: /Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang-tools-extra/test/clang-doc/basic-project.test

-dump-input=help explains the following input dump.

Input was:
<<<<<<
�[1m�[0m�[0;1;30m            1: �[0m�[1m�[0;1;46m<!DOCTYPE html> �[0m
�[0;1;30m            2: �[0m�[1m�[0;1;46m<meta charset="utf-8"/> �[0m
�[0;1;30m            3: �[0m�[1m�[0;1;46m<title>class Shape</title> �[0m
�[0;1;30m            4: �[0m�[1m�[0;1;46m<link rel="stylesheet" href="../clang-doc-default-stylesheet.css"/> �[0m
...