On the way to a cheaper and more scalable stack frame representation
for the inspector (crbug/1258599), this removes the need to expose
both what was called "function name" and what was called "function
debug name" on a v8::StackFrame instance.

The reason to having a distinction between that the V8 API exposes
and what the inspector exposes as frame function name is that after
the initial refactoring around v8::internal::StackFrameInfo, some
wasm cctests would still dig into the implementation details and
insist on seeing the "function name" rather than the "function
debug name". This CL now addresses that detail in the wasm cctests
and going forward unifies the function names used by the inspector
and the V8 API (which is not only needed for internal consistency
and reduced storage requirements in the future, but also because
Blink for example uses v8 API and v8_inspector API interchangeably
and assumes that they agree, even though at this point Blink
luckily wasn't paying attention to the function name):

- The so-called "detailed stack trace", which is produced for the
  inspector and exposed by the v8 API, always yields the "function
  debug name" (which for example in case of wasm will be a WAT
  compatible name),
- while the so-called "simple stack trace", which is what is used
  to implement the CallSite API and underlies Error.stack continues
  to stick to the "function name" which in case of wasm is not
  WAT compatible).

Bug: chromium:1258599
Change-Id: Ib15d038f3ec893703d0f7b03f6e7573a38e82b39
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3312274Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Simon Zünd <szuend@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78283}