When GetBytecodeOffsetForBaselinePC() is called with a PC that is inside
the baseline prologue, correctly return kFunctionEntryOffset now.

Bug: v8:11420
Change-Id: I39cb96a04e7d92d0ba5dfcbcaeebd23144c9df05
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2773050
Auto-Submit: Patrick Thier <pthier@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Patrick Thier <pthier@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73601}