Port ae03752f
https://crrev.com/c/2102574

Original Commit Message:

  This implements inspection of live registers on breakpoints in Liftoff.
  To that end, the frame pointer of the WasmDebugBreak frame is remembered
  when iterating the stack. Based on a platform-specific implementation of
  {WasmDebugBreakFrameConstants}, the offset of the respective register
  within that frame is computed, and the value is read from the frame.

  As a drive-by, the wasm debug side table is storing register codes as
  liftoff codes, which can also store register pairs (needed for i64 on
  32-bit platforms, and for SIMD, which is not supported yet).

Change-Id: I88bcc5256e1a3b4447c727673178c41fbdd04df4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2105506
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66772}