JIT-EE Interface extension

1 — Goal

Implement one new JIT-VM (also known as JIT-EE) API and all supporting glue. The JIT-VM interface defines the APIs through which the JIT compiler communicates with the runtime (VM).

2 — Required user inputs

Ask the user for a C-like signature of the new API if it's not provided. Suggest <repo_root>/src/coreclr/tools/Common/JitInterface/ThunkGenerator/ThunkInput.txt file as a reference. Example:

CORINFO_METHOD_HANDLE getUnboxedEntry(CORINFO_METHOD_HANDLE ftn, bool* requiresInstMethodTableArg);

3 — Implementation steps (must be completed in order)

NOTE: When inserting new entries/methods into any of the files below, their position and ordering does not matter. Any suggested placement (e.g. "at the end" or "near similar signatures") is just a convenient default, not a requirement.