deps: cherry-pick 6bc4bfe from V8 upstream

Only changes to src/base/debug/stack_trace_posix.cc included

Original commit message:
    Fixes to V8 GN build process on aix platform

    src/base/debug/stack_trace_posix.cc: suppressed unused function warnings
    for functions DemangleSymbols, OutputPointer(in order to compile with
    -Werror flag)

    test/cctest/test-isolate-independent-builtins.cc: corrections to make
    ByteInText test case compatible with aix. (affects aix only)

    Change-Id: I49e45e63545404c77aaed3f51b26557f6f03455e
    Reviewed-on: https://chromium-review.googlesource.com/927484


Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
    Commit-Queue: Jakob Gruber <jgruber@chromium.org>
    Cr-Commit-Position: refs/heads/master@{#52071}

PR-URL: https://github.com/nodejs/node/pull/23958


Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Beth Griggs <Bethany.Griggs@uk.ibm.com>
Reviewed-By: George Adams <george.adams@uk.ibm.com>