Allow trimming NativeRuntimeEventSource

[MichalStrehovsky]

Constant propagation cannot see through the local assignments/reassignments.

Matches the existing patterns at

runtime/src/libraries/System.Private.CoreLib/src/System/Threading/Lock.cs

Lines 696 to 697 in f2b3030

	// Also check NativeRuntimeEventSource.Log.IsEnabled() to enable trimming
	if (areContentionEventsEnabled && NativeRuntimeEventSource.Log.IsEnabled())

[Copilot]

Pull request overview

This PR updates CoreLib’s threading event emission sites to include an additional NativeRuntimeEventSource.Log.IsEnabled() guard so the ILLink substitutions for EventSource.IsEnabled() (when EventSource.IsSupported is feature-switched off) can more reliably trim away the NativeRuntimeEventSource-dependent code, even when existing boolean locals are reassigned.

Changes:

• Add && NativeRuntimeEventSource.Log.IsEnabled() to WaitHandle wait start/stop event emission guards.
• Add && NativeRuntimeEventSource.Log.IsEnabled() to Lock contention event emission guards (start/stop/created).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/libraries/System.Private.CoreLib/src/System/Threading/WaitHandle.cs	Adds an extra IsEnabled() guard around wait ETW/EventPipe event writes to improve trim-friendliness under EventSource.IsSupported=false.
src/libraries/System.Private.CoreLib/src/System/Threading/Lock.cs	Adds an extra IsEnabled() guard around contention event writes to match existing trim-friendly patterns in this file.