"AbsoluteDivSmall" had a shortcut path for abs(divisor) == 1 where
it would simply return the dividend as result. However, its caller
"Divide" was blissfully ignorant of this trick and would therefore
simply set the value's sign as needed, modifying the input.
This CL prevents that, while continuing to avoid the full division
algorithm for abs(divisor) == 1.

Bug: v8:6791
Change-Id: I04cdc93f5ed2a696587c35c754e68f07012dd1a9
Reviewed-on: https://chromium-review.googlesource.com/772332
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49433}