Port d710756a

Original Commit Message:

    This is the last remaining missing instruction from the MVP. This CL
    adds support for ia32, x64, arm, and arm64.
    For CPUs which do not support the POPCNT instruction, there exists a
    fallback implementation in C.

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

Change-Id: I8965f4312c5e8ac6510c754772ba3d60394dfc4a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1899908Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
Commit-Queue: Milad Farazmand <miladfar@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#64778}