The flag is on by default, and tests already rely on the new behaviour.
This CL removes the flag and immediately affected code. More code will
be removed component by component in follow-up CLs.

Drive-by: Inline {RemoveBreakpointFromInfo} into {ClearBreakPoint},
which only redirected to that method after this CL.

R=thibaudm@chromium.org,bmeurer@chromium.org

Bug: v8:10389, v8:10351
Change-Id: I3b18e228dd633cfb25541ddd0f31699b1ceb1db0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2154804
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67244}