Although the code generator already combines return instructions late
in the pipeline into a common site, there were still superfluous jumps
to that common site left in the code.

Change-Id: I06c885fb0ab6a2c078f9dabdc6616c6881f42c75
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2284984
Commit-Queue: Daniel Clifford <danno@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69133}