Port 9c4ffc38

Original Commit Message:

    In fact, shifts are used most often with a fixed shift amount. This CL
    adds special handling for this in Liftoff, to generate shorter and
    faster code.

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

Change-Id: I20f8cfa6930bc20eb8db33a99bd07fce49f3f74d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1899907Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
Commit-Queue: Milad Farazmand <miladfar@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#64777}