Revert "[Sampling profiler] Move context frame recording outside the native unwinders"

This reverts commit a92a56cb6ed4b7f7bb4fb19d94e00bf3b55fa417.

Reason for revert: Causes flaky test failures on module lookups.

Original change's description:
> [Sampling profiler] Move context frame recording outside the native unwinders
> 
> Allows the native unwinders to be used to unwind from arbitrary frames,
> not just from the context frame. This is required to support restarting
> native frame unwinding after v8 unwinding.
> 
> Bug: 909957
> Change-Id: I8c87d26c981f98bd842aa8467fcc23faffdec7b0
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1540285
> Commit-Queue: Mike Wittman <wittman@chromium.org>
> Reviewed-by: Leonard Grey <lgrey@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#646333}

TBR=wittman@chromium.org,lgrey@chromium.org

Change-Id: I34491f940d3390d6c5ec0dadfe83532a8a05e564
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 909957, 948302
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1548362
Reviewed-by: Mike Wittman <wittman@chromium.org>
Commit-Queue: Mike Wittman <wittman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#646509}
5 files changed