deps: update perfview (removes the .il suffix from profile module names)

[jamescrosswell]

Bumps the perfview submodule from e343a0cf (v3.1.15-5) to 9c4f637c (v3.2.6-3) — 227 commits.

The reason for doing it now is microsoft/perfview#2452, which adds
TraceLog.TrimLiveSessionState(): the API needed to bound the call stack interning growth behind
#5469. This PR does not fix that leak — it only makes the API available by bumping to the appropriate version of perfview.

Regenerating sample.etlx

TraceLogProcessorTests loads a committed sample.etlx, whose ETLX format version is tied to the
TraceEvent build — the new FastSerialization accepts >= 78 and the committed copy was 74, so it
failed to load after the bump. It has been regenerated at the current version and re-committed.

An earlier revision of this PR deleted it instead and let the test rebuild it from sample.nettrace
on demand, since it goes stale on every submodule bump. That turned out to be the wrong trade:
_resourcesPath resolves to the shared source Resources directory for every target framework,
and dotnet test runs one host per TFM, so they raced on both sample.etlx and the
sample.etlx.new temp TraceEvent writes beside it. That failed on .NET (win-arm64) with
the process cannot access the file ... because it is being used by another process.

Committing it removes the writes entirely rather than trying to synchronise them. The staleness
problem that motivated the removal is now handled by documentation instead: Resources/README.md
covers how to regenerate, including the error that signals it is needed.

Two hardening fixes from review remain, since they protect whoever next regenerates the fixture and
runs that path deliberately: the reflection lookup now throws if the target moves, rather than
silently no-opping into a confusing file-not-found, and the EventPipeEventSource is disposed
(upstream's own CreateFromEventPipeDataFile wraps it the same way).

Snapshot change

Both verified snapshots change in one way only: module names lose a spurious .il suffix (System.Private.CoreLib.il → System.Private.CoreLib). 68 of the 70 changed lines are that rename and the other two are a trailing newline.

These names surface in profile frames, so this is a small user-visible improvement.

Note on the NuGet package

4cfd9f57 Bump version to 3.2.6 landed upstream before our fix, so the fix is not in the 3.2.6
release — it will be in the next one. Until then the submodule remains necessary; switching
Sentry.Profiling back to a PackageReference is something we could consider in the future.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.78%. Comparing base (2be688c) to head (a9f09c4).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5502      +/-   ##
==========================================
- Coverage   74.87%   74.78%   -0.09%     
==========================================
  Files         513      513              
  Lines       18659    18759     +100     
  Branches     3636     3669      +33     
==========================================
+ Hits        13970    14029      +59     
- Misses       3819     3856      +37     
- Partials      870      874       +4     

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[jamescrosswell]

This is the point of this particular change in the PR - gives a meaningful error if the signature ever changes.

[vaind]

IDK the current state but previously some of the tests have been disabled (at least in CI?) as flaky. How is this change tested?