Port 48a3227b

Original commit message:
    When reserving a stack slot for the receiver, push an Immediate(0)
    rather than a register that contains an untagged integer.
    All other platforms push zero already.

R=jkummerow@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=

Review URL: https://codereview.chromium.org/1588053003

Cr-Commit-Position: refs/heads/master@{#33314}