Port 9dfe6359

Original Commit Message:

    Pushes the optimised code path to after the main interpreter path, so
    the straightline path is just normal interpretation.

R=delphick@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Change-Id: Ib275871fd8463bf6879ab1ab78e9b4146df98251
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1838611
Commit-Queue: Milad Farazmand <miladfar@ca.ibm.com>
Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#64097}