[clr-interp] Improve the performance of interpreter calls

[davidwrighton]

• Instead of setting the target in the CallStubHeader at each invocation, store the target in the CallStubHeader immediately.
• Avoid invoking the prestub unnecessarily. Instead, detect that we've already run the prestub to completion at least once before poisoning the m_interpreterCode field on MethodDesc.

This may be enough to make some of our tests which are currently timing out pass.

[dotnet-policy-service]

Tagging subscribers to this area: @mangod9
See info in area-owners.md if you want to be subscribed.

[davidwrighton]

/azp run runtime-interpreter

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[davidwrighton]

/azp run runtime-interpreter

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[Copilot]

Pull Request Overview

This PR optimizes interpreter call performance by reducing redundant work and avoiding unnecessary prestub invocations. The changes focus on storing call targets in CallStubHeader immediately rather than setting them at each invocation, and implementing a poisoning mechanism to prevent repeated failed attempts to get interpreter code.

• Store call targets in CallStubHeader at creation time to avoid repeated target setting
• Add poisoning mechanism to prevent redundant prestub calls for methods that cannot be interpreted
• Optimize call paths by detecting when prestub has already completed successfully

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
src/coreclr/vm/wasm/helpers.cpp	Updates InvokeManagedMethod to handle NULL target by getting multi-callable address
src/coreclr/vm/method.hpp	Adds interpreter code poisoning mechanism with new methods and constants
src/coreclr/vm/interpexec.cpp	Major optimization changes including target storage in CallStubHeader and poisoning logic
src/coreclr/vm/callstubgenerator.h	Adds GetTarget() method to CallStubHeader for retrieving stored targets