Mask used in MacroAssembler::TestJSArrayForAllocationMemento was not supposed
to shifted right by 16 bits before loaded in to register r0.

R=michael_dawson@ca.ibm.com,mbrandy@us.ibm.com,joransiu@ca.ibm.com
BUG=

Review URL: https://codereview.chromium.org/1852403002

Cr-Commit-Position: refs/heads/master@{#35247}