RFR: 8257436: [aarch64] Regressions in ArrayCopyUnalignedDst.testByte/testChar for 65-78 bytes when UseSIMDForMemoryOps is on

[Evgeny Astigeevich]

Copying data in range 65 - 80 bytes with
ldpq
ldpq 
ldp
stpq
stpq
stp
is faster than with
ldpq
ldpq
ldpq
stpq
stpq
stpq
This fixes regressions of ArrayCopyUnalignedDst.testByte/testChar when UseSIMDForMemoryOps is on.
See the attached results for performance data
[test_byte_results.txt](https://github.com/openjdk/jdk/files/5628447/test_byte_results.txt)
[test_char_results.txt](https://github.com/openjdk/jdk/files/5628451/test_char_results.txt)
[test_int_results.txt](https://github.com/openjdk/jdk/files/5628462/test_int_results.txt)
[test_long_results.txt](https://github.com/openjdk/jdk/files/5628468/test_long_results.txt)

-------------

Commit messages:
 - 8257436: [aarch64] Regressions in ArrayCopyUnalignedDst.testByte/testChar for 65-78 bytes when UseSIMDForMemoryOps is on

Changes: https://git.openjdk.java.net/jdk/pull/1558/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1558&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8257436
  Stats: 12 lines in 1 file changed: 12 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1558.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1558/head:pull/1558

PR: https://git.openjdk.java.net/jdk/pull/1558