Redefinition of GetHalfStackSlot after commit 5ea59597.

Change-Id: Ib2b1fe6bd130c6737a73ef55b09dc80f4cd9b3fb
Reviewed-on: https://chromium-review.googlesource.com/c/1396077Reviewed-by: Sreten Kovacevic <skovacevic@wavecomp.com>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Predrag Rudic <prudic@wavecomp.com>
Cr-Commit-Position: refs/heads/master@{#58543}