Fix Frame::AlignSavedCalleeRegisterSlots

Fix Frame::AlignSavedCalleeRegisterSlots

The return value is expected to be the number of padding slots added to the frame. However, the original logic would return -1 if padding was required, so insufficient stack space would be reserved.

This function now returns either 0 or 1, as the existing calling code expects.

BUG=

Review URL: https://codereview.chromium.org/1369303002

Cr-Commit-Position: refs/heads/master@{#30994}