This reduces CEntryStub code size by 64 bytes, and reduces CallApiCallbackStub
by 27 bytes.

Change-Id: I46479077f61fdae6b260ca28c67df3509dee5c1a
Reviewed-on: https://chromium-review.googlesource.com/963652
Commit-Queue: Kanghua Yu <kanghua.yu@intel.com>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52005}