[WIP][clr-interp] Add User Breakpoint Support for Interpreter Debugging

[matouskozak]

This PR implements support for setting and handling user breakpoints (System.Diagnostics.Debugger.Break()) in interpreted code.

Key Changes

Execution Control Abstraction (executioncontrol.h/cpp)

• Introduced IExecutionControl interface to abstract breakpoint operations across different execution strategies. Currently just for interpreter but will be extended to other codegens.
• Implemented InterpreterExecutionControl class for interpreter-specific bytecode patching
• ApplyPatch(): Replaces bytecode instruction with INTOP_BREAKPOINT opcode
• UnapplyPatch(): Restores original bytecode instruction

Patch Mechanism:

• Interpreter breakpoints work by patching bytecode directly with INTOP_BREAKPOINT instruction
• Original opcode is saved in the patch structure for restoration

Exception Flow:

1. Interpreter hits INTOP_BREAKPOINT opcode
2. Raises STATUS_BREAKPOINT exception with bytecode context
3. Exception filter routes to FirstChanceNativeException()
4. Debugger controller dispatches to appropriate breakpoint handler
5. Original opcode is restored during patch skip activation

Address Handling:

• Interpreter breakpoints use bytecode addresses, not native addresses
• Special handling in patch matching to avoid comparing bytecode address with native IP
• Exception information provides both bytecode address and frame context

TODOs

• JIT completion notification handling needs revisiting for interpreter code. I've disabled it as it wasn't needed for user breakpoints.
• IP adjustment logic uses hardcoded 3-byte offset. Not sure what is the reason for that...
• When I tried calling FirstChanceNativeException() directly from InterpBreakpoint, I hit issues with thread and stack limit asserts, thus I went back to raising and filtering the exception.

[kotlarmilos]

Once the JIT abstraction is implemented, can we remove this condition?

[matouskozak]

Yes, if we implement the HardwareExecutionControl, we should be able to just call pJitManager->GetExecutionControl()->ApplyPatch(patch); without any checks.