With boolean validation, we don't keep the PC for stack values any more.
This CL fixes the --trace-wasm-decoding logic to just not print the
opcode which produced a value. The producer can also be found by looking
back in the trace.
This also makes the tracing output a lot more concise, hence easier to
read.

Also fix the TraceFailed method to not try to print buffer relative
offsets if no PC is there.

R=zhin@chromium.org

Bug: v8:10969
Change-Id: I5a7a69ea5aa461a277401d87ee24635266517d3c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2465837Reviewed-by: Zhi An Ng <zhin@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70501}