This reverts commit c3ac338b.

Reason for revert: Breaks stepping with `n`

Original change's description:
> [tools] Add a simple gdb frame unwinder
>
> Add a simple unwinder for gdb which, on x64,  walks frame pointers
> whenever there is no source information available. Ideally we would only
> do this for V8 PCs but this appears hard to do in an Unwinder without
> messing with gdb's internal assumptions.
>
> Change-Id: Iba1e62a3768340ee912e81d691237c1920a8ae91
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3608628
> Reviewed-by: Camillo Bruni <cbruni@chromium.org>
> Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#80204}

Change-Id: I0264cf34cfe8fe2331bacf202dedbb4706535936
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3644855
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80493}