[wasi][R2R] MetadataLoadContext tests cannot find assembly IL

[lewing]

Description

With CoreCLR WASI ReadyToRun, 482 of 606 test cases in System.Reflection.MetadataLoadContext.Tests fail:

System.Exception : Could not find the IL for assembly System.Reflection.MetadataLoadContext.Tests, Version=11.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ff...
   at System.Reflection.Tests.TestUtils.Project(Type type)

A further 54 report the same for System.Private.CoreLib. The tests locate the IL image of a loaded assembly on disk and load it into a MetadataLoadContext.

The suite passes in the non-R2R CoreCLR WASI lane, so this is specific to ReadyToRun. In the WASI R2R layout, the app loads its assemblies from the composite stubs under managed/comp/ and keeps the IL copies in managed/. The location the tests derive no longer points at an IL image.

Possible directions: make the tests find the IL copies in the ReadyToRun layout, or make the runtime report the IL file location for composite-backed assemblies.

Seen on #134813 in a local trimmed ReadyToRun run.

Note

This issue was drafted with the help of GitHub Copilot.

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