[clr-interp] Report async-suspension locals to the debugger via GetAsyncLocals

[kotlarmilos]

Description

When a managed async method is suspended at an await, the right-side debugger asks for the live values of the user's locals and arguments at that suspension point so they can be displayed on the call stack. The JIT path supplies this through ICorJitInfo::reportAsyncDebugInfo. The interpreter compiler never hits that path, so ICorDebugAsyncFrame::GetArgument returned CORDBG_E_IL_VAR_NOT_AVAILABLE for every IL variable on every interpreted async frame.

This adds a small parallel pipeline for the interpreter. InterpAsyncSuspendData now carries a per suspension point table of {ilVarNum, dataOffset} entries. On the DAC side, GetAsyncLocals detects an interpreter method and decodes the bytecode at startIp + state.

This fixes the following interpreter debugger test failures:

• Async.AsyncSimple
• Async.AsyncBreakpoint
• Async.AsyncBreakpointJmc
• Async.AsyncGeneric
• Async.AsyncRecursive
• Async.AsyncSharedGeneric
• Async.AsyncV2CallingAsyncV1Iterator
• Async.AsyncGenericStepInto

[Copilot]

Pull request overview

This PR extends CoreCLR’s interpreter async-debugging support so the right-side debugger can retrieve live async locals/arguments for interpreted async frames via DacDbiInterfaceImpl::GetAsyncLocals, analogous to the existing JIT DebugInfoStore pipeline.

Changes:

• Introduces InterpAsyncDebugVar and adds a per-suspension-point { ilVarNum, dataOffset } table to InterpAsyncSuspendData.
• Emits and persists interpreter async-local debug metadata during EmitSuspend, storing the debug-var tables in the finalized method data.
• Updates the DAC GetAsyncLocals implementation to detect interpreted methods, decode the suspension-point bytecode via state, and surface interpreter async locals to the debugger.

Show a summary per file

File	Description
src/coreclr/interpreter/inc/interpretershared.h	Adds interpreter async debug-var metadata types/fields carried per suspension point.
src/coreclr/interpreter/compiler.cpp	Captures IL var → continuation offset mappings at suspend points and persists them into the unified method allocation.
src/coreclr/debug/daccess/dacdbiimpl.cpp	Implements interpreter-aware GetAsyncLocals decoding to return async locals for interpreted frames.

Copilot's findings

• Files reviewed: 3/3 changed files
• Comments generated: 3

[Copilot]

Copilot's findings

• Files reviewed: 3/3 changed files
• Comments generated: 1

[Copilot]

Copilot's findings

• Files reviewed: 4/4 changed files
• Comments generated: 1

[BrzVlad]

Seems like this code doesn't belong here, in EmitCode. Could we extract it in some other method and move it outside of this. I would also move the setVars block above

[kotlarmilos]

Extracted into InterpCompiler::ReportAsyncDebugInfo(), called from EmitCode after setVars/setBoundaries

[Copilot]

Copilot's findings

• Files reviewed: 4/4 changed files
• Comments generated: 0 new