[gn build] Port e606dc1

Author: llvmgnsyncbot

llvm/utils/gn/secondary/clang/lib/AST/BUILD.gn

@@ -61,6 +61,7 @@ static_library("AST") {
     "ASTTypeTraits.cpp",
     "AttrDocTable.cpp",
     "AttrImpl.cpp",
+    "Availability.cpp",
     "CXXInheritance.cpp",
     "Comment.cpp",
     "CommentBriefParser.cpp",

llvm/utils/gn/secondary/clang/lib/ExtractAPI/BUILD.gn

@@ -12,7 +12,6 @@ static_library("ExtractAPI") {
   sources = [
     "API.cpp",
     "APIIgnoresList.cpp",
-    "AvailabilityInfo.cpp",
     "DeclarationFragments.cpp",
     "ExtractAPIConsumer.cpp",
     "Serialization/SymbolGraphSerializer.cpp",