Quick: Handle total high/low register overlap on arm/mips.

OpRegCopyWide() in arm and mips backends didn't handle the
total register overlap when the registers holding the source
and destination pairs are the same but in reverse order.

Bug: 21897012

(cherry picked from commit 8958f7f8702327e713264d0538ab5dec586f3738)

Change-Id: I20afce6cc3213e7f7b3edaef91f3ec29c469f877
2 files changed