Make GCDump work on Linux

[MichalStrehovsky]

Fixes #116686.

Turns out the test was failing because everything involved in GCDump was disabled outside Windows.

Cc @dotnet/ilc-contrib

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[Copilot]

Pull Request Overview

This PR re-enables GCDump functionality on Linux by removing OS-specific exclusions and adapting ETW and interlocked calls for cross-platform support.

• Removes the Linux-specific test exclusion for GCDump so tests now run on Linux.
• Un-guards and adjusts the ETW heap-walk helper and event tracing code for non-Windows builds.
• Updates atomic exchange calls, header includes, and adds null-safety in bulk-type event logging.

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/tests/issues.targets	Removed the Linux exclusion for tracing/eventpipe/gcdump to allow the GCDump test to run on Linux.
src/coreclr/nativeaot/Runtime/profheapwalkhelper.cpp	Dropped the FEATURE_ETW guard so heap walking runs on Linux.
src/coreclr/nativeaot/Runtime/eventtrace_gcheap.cpp	Swapped Windows-only InterlockedExchange64 for PalInterlockedExchange64 for portability.
src/coreclr/nativeaot/Runtime/eventtrace_bulktype.cpp	Fixed casing on include, added nothrow allocation and null check, and ensured a default case.
src/coreclr/nativeaot/Runtime/eventtrace.h	Removed fallback inline stubs for non-ETW builds (now absent).
src/coreclr/nativeaot/Runtime/eventtrace.cpp	Changed filter parsing to skip on Unix and removed the FEATURE_ETW guard around ForceGC.
src/coreclr/nativeaot/Runtime/eventpipe/CMakeLists.txt	Reordered sources to include profheapwalkhelper.cpp under the eventtrace list.

Comments suppressed due to low confidence (3)

src/coreclr/nativeaot/Runtime/profheapwalkhelper.cpp:175

• This ETW call is now unconditionally compiled on all platforms, but the ETW methods may not be defined when FEATURE_ETW is disabled, leading to build errors. Consider reintroducing the FEATURE_ETW guard or providing stub declarations.

    if (ETW::GCLog::ShouldWalkHeapObjectsForEtw())

src/coreclr/nativeaot/Runtime/eventtrace.cpp:277

• The ForceGC call was previously guarded by FEATURE_ETW. With the guard removed, this call will be compiled when ETW support is absent, leading to missing symbols. Re-add an appropriate guard or ensure the methods exist on Linux.

        ETW::GCLog::ForceGC(l64ClientSequenceNumber);

[MichalStrehovsky]

/azp run runtime-nativeaot-outerloop

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[MichalStrehovsky]

/azp run runtime-nativeaot-outerloop

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Azure Pipelines successfully started running 1 pipeline(s).