Port de2681c1

Original Commit Message:

    This adds a {PrintRegister} method which prints the given register in a
    readable way (e.g. "eax", ... on ia32).
    This is currently only used in Liftoff. The {RegisterConfiguration}
    class has the same functionality, and I plan to make
    {RegisterConfiguration} also use the new {RegisterName} functions in a
    follow-up CL.

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

Change-Id: I8359ed22ebe88d5c30a45a9c6f3caa3b03d902ee
Reviewed-on: https://chromium-review.googlesource.com/c/1344509
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#57698}