[aarch64-port-dev ] RFR: 8148328: aarch64: avoid unnecessary lsr instructions in stub code

[Felix Yang]

Hi,

Please review the following webrev:
http://cr.openjdk.java.net/~fyang/8148328/webrev.00/

Jira issue: https://bugs.openjdk.java.net/browse/JDK-8148328

This trivial patch eliminates unnecessary lsr instructions in
jbyte_arraycopy and jbyte_disjoint_arraycopy stub.

Tested with jtreg hotspot & langtools.  Is it OK?

Thanks,
Felix.