[aarch64-port-dev ] RFR: JDK-8184900 AArch64: Fix overflow in immediate cmp instruction

[Yang Zhang]

Hi, all

For a fastdebug build openjdk in jdk10/hs tree, there is a failed test
case (TestOptionsWithRanges) in jtreg. The reason is that the
immediate cmp instruction has 12 significant bits. This causes an
overflow in TestOptionsWithRanges.

With this patch, TestOptionsWithRanges can be passed and there aren't
new failed test cases in jtreg.

Bug:
https://bugs.openjdk.java.net/browse/JDK-8184900

Webrev:
http://cr.openjdk.java.net/~yzhang/8184900/webrev.00/

Please help to review it.

Regards,
Yang