Fix diagnostic for calls on marshalled delegates

[jkotas]

• Fix diagnostic for calls on marshalled delegates. It got broken by switch to precode thunks.
• Add test for diagnostic for calls on marshalled delegates.
• Pass UMEntryThunkData* around in the delegate marshaling code instead of UMEntryThunk*. This avoids constant back and forth hops between the two.

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[Copilot]

Pull Request Overview

This PR restores and enhances diagnostics for calls on marshalled delegates by switching from UMEntryThunk* to UMEntryThunkData* and adding a test to verify the behavior.

• Added an unhandled exception check for collected delegates and a new test project/source (collecteddelegate)
• Refactored runtime delegate marshaling code to pass and operate on UMEntryThunkData* instead of UMEntryThunk*
• Introduced CallbackOnCollectedDelegate to emit a fail-fast message when invoking a collected delegate

Reviewed Changes

Copilot reviewed 20 out of 20 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/tests/baseservices/exceptions/unhandled/unhandledTester.cs	Assert the correct diagnostic message for a collected delegate scenario
src/tests/baseservices/exceptions/unhandled/collecteddelegate.csproj & .cs	New test project and source triggering a callback on a collected delegate
src/coreclr/vm/dllimportcallback.h / dllimportcallback.cpp	Updated APIs to use UMEntryThunkData*, added CallbackOnCollectedDelegate
src/coreclr/vm/syncblk.h / syncblk.cpp	Changed member types and getters to UMEntryThunkData*
src/coreclr/vm/comdelegate.cpp	Adjusted COM delegate marshaling to the new UMEntryThunkData interface
src/coreclr/vm/stubmgr.cpp	Updated reverse P/Invoke tracing to accept UMEntryThunkData*

Comments suppressed due to low confidence (2)

src/coreclr/vm/dllimportcallback.cpp:230

• Missing semicolon after CallbackOnCollectedDelegate(pUMEntryThunkData), causing a compile error.

        CallbackOnCollectedDelegate(pUMEntryThunkData)

src/coreclr/vm/comdelegate.cpp:1435

• pUMEntryThunk is now a UMEntryThunkData* and does not have a GetData() method; this call will not compile. Consider adding a GetObjectHandle() method to UMEntryThunkData or calling the correct accessor directly on pUMEntryThunk.

        ? pUMEntryThunk->GetData()->GetObjectHandle()