JIT: Timeout in libraries-pgo tests

[jakobbotsch]

Quite a few timeouts in x86 (and some other runs). Smaller number in other platforms.
Example pipeline run: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1179410&view=results
Example x86 console log: https://helixr1107v0xdcypoyl9e7f.blob.core.windows.net/dotnet-runtime-refs-heads-main-d5f58b4e6d2846888a/System.Memory.Tests/1/console.a5759d34.log?helixlogtype=result
Example x64 console log: https://helixr1107v0xdcypoyl9e7f.blob.core.windows.net/dotnet-runtime-refs-heads-main-7af6aae6ada343fb96/System.Memory.Tests/1/console.31e7ab50.log?helixlogtype=result

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[MihuBot]

I'm a bot. Here is a possible related and/or duplicate issue (I may be wrong):

• JIT: libraries PGO tests time out #59667

[AndyAyersMS]

I think we've seen this before: the DOTNET_JitInstrumentIfOptimizing=1 mode is very slow as it is forcing all optimized methods to have instrumentation.

Not sure what to do about this yet. We may get enough coverage with normal testing (eg all R2R methods+inlinees will end up at this tier if called enough), but maybe not.