Remove new aligned memcpy path for cortex-a15.

For some reason the new cortex-a15 memcpy code from ARM is really bad
for really large copies. This change forces us to go down the old path
for all copies.

All of my benchmarks show the new version is faster for large copies, but
something is going on that I don't understand.

Bug: 10838353
Change-Id: I01c16d4a2575e76f4c69862c6f78fd9024eb3fb8
1 file changed