tools: Remove rebase_for_review script.
tools: Remove rebase_for_review script.

./tools/cl supports rebasing now.

BUG=None
TEST=None

Change-Id: I94f46da2a37d2061714420ad040fe15074b55cd3
Reviewed-on: https://chromium-review.googlesource.com/c/crosvm/crosvm/+/3833797
Tested-by: Junichi Uekawa <6bd240a6ce32463e272bb69c685a8e946b33ac05@chromium.org>
Reviewed-by: Dennis Kempin <cd09796fb571bec2782819dbfd33307f65b1c778@google.com>
Commit-Queue: Junichi Uekawa <6bd240a6ce32463e272bb69c685a8e946b33ac05@chromium.org>

google/crosvm,google/crosvm,google/crosvm,google/crosvm