Portable EntryPoint feature

[AaronRobinsonMSFT]

Start implementation of the Portable EntryPoint feature.

Remove all WASM specific code from the precode paths and define out precode types when FEATURE_PORTABLE_ENTRYPOINT is defined. This is currently limited to WASM, but is being developed in a WASM agnostic manner.

This is only part 1 of the work. All Precode stubs that assert need to be removed. The current WASM progress is basically unchanged with these changes, in the sense it has not regressed further.

There was also disabling of specific runtime features, which resulted in various clean-up.

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[Copilot]

Pull Request Overview

This PR implements the initial foundation for a Portable EntryPoint feature to abstract away execution strategies on platforms that don't allow dynamic code generation. The changes remove WASM-specific code from precode paths and introduce a new PortableEntryPoint class that can be used across platforms.

Key changes include:

• Introduction of FEATURE_PORTABLE_ENTRYPOINTS feature flag and corresponding infrastructure
• Creation of new portable entry point implementation with stub methods for precode compatibility
• Refactoring of tiered compilation and interpreter code to work without platform-specific assumptions
• Clean-up of WASM-specific precode code and various runtime feature conditionals

Reviewed Changes

Copilot reviewed 29 out of 31 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/coreclr/vm/wasm/cgencpu.h	Removes WASM-specific precode feature definitions
src/coreclr/vm/util.hpp	Changes EEThreadId from void pointer to SIZE_T for better type safety
src/coreclr/vm/tieredcompilation.h/.cpp	Moves IsTieringDelayActive method outside feature guards for broader availability
src/coreclr/vm/precode_portable.hpp/.cpp	Adds new portable entry point implementation with stub methods
src/coreclr/vm/precode.h/.cpp	Wraps traditional precode code in feature guards and removes WASM-specific code
src/coreclr/vm/prestub.cpp	Adds portable entry point support for interpreter code paths
src/coreclr/vm/method.hpp/.cpp	Integrates portable entry points into method descriptor infrastructure
src/coreclr/vm/jitinterface.cpp	Updates JIT interface to handle portable entry points for interpreted code
src/coreclr/vm/interpexec.cpp	Updates interpreter execution to work with portable entry points
src/coreclr/interpreter/interpretershared.h	Minor formatting improvements to struct members
Various build files	Adds feature flags and build configuration for portable entry points

[AaronRobinsonMSFT]

Yay for green! @kg@jkotas@janvorli PTAL.

[kg]

LGTM, i don't know these areas super well though so more eyes on it would be good

[jkotas]

LGTM!

[AaronRobinsonMSFT]

/ba-g Unrelated WASM on mono failures