Port 7c45b005

Original commit message:
    This passes the new.target value in a register instead of through a
    side-channel via the construct stub. Note that only TurboFan code uses
    the register value so far, but unoptimized code will be switched soon.

R=mstarzinger@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=v8:4544
LOG=n

Review URL: https://codereview.chromium.org/1469283004

Cr-Commit-Position: refs/heads/master@{#32231}