Changes

Add options to select the threshold for using rep movs in arraycopy

`arraycopyRepMovsByteArrayThreshold`
- Byte array copy threshold for using REP MOVS instructions.
- Only supports 32 or 64 bytes

`arraycopyRepMovsCharArrayThreshold`
- Char array copy threshold for using REP MOVS instructions.
- Only supports 32 or 64 bytes.

`arraycopyRepMovsIntArrayThreshold`
- Int array copy threshold for using REP MOVS instructions.
- Only supports 32, 64, or 128 bytes.

`arraycopyRepMovsLongArrayThreshold`
- Long array copy threshold for using REP MOVS instructions.
- Only supports 32, 64, or 128 bytes.

`arraycopyRepMovsReferenceArrayThreshold`
- Reference array copy threshold for using REP MOVS instructions.
- Only supports 32, 64, or 128 bytes.

Signed-off-by: Annabelle Huo <Annabelle.Huo@ibm.com>
 (commit: bcf5c45)