Int64AbsWithOverflow should have 2 return value, the 2nd one should
indicate whether it's overflow or not.

This causes a debug failure on s390x.

Change-Id: I2874227751d5874b47e63fed9e8f085f5165a44d
Reviewed-on: https://chromium-review.googlesource.com/1255642Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#56343}