Instead of two copies of the lookup code in frames.cc and wasm-debug.cc,
put one lookup method on the WasmCode. This is where it belongs really,
since the WasmCode is the main input to the function (besides the
offset).

Also refactor how source positions are computed in WasmCompiledFrame.
Avoid going through the summary, which is unneccessarily complex. This
also adds another {byte_offset} accessor which can be used for
debugging.

Bug: v8:10235
Change-Id: I5c545ee302754b86009f09bedc5ff6e39ba664f6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2135726Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66991}