[11u] RFR (S) 8249189: AARCH64: more L2I conversions can be skipped

[Dmitry Chuyko]

Hello,

Original RFE: https://bugs.openjdk.java.net/browse/JDK-8249189

aarch64_ad.m4 and aarch64.ad are decorated different in 11u. 
Nevertheless changes are very straightforward.

aarch64_ad.m4
Reapplied changes for UBFIZ_INSN and it's usages.

aarch64.ad
Following the original patch: operand immL_positive_bitmaskI added after 
operand immI_bitmask, instruct ubfizwIConvI2L and ubfizLConvL2I added 
between ubfizL and ubfizIConvI2L, instruct ubfizLConvL2Ix added after 
ubfizIConvI2L.

Mask type is changed long to keep it in line with the rest of the .ad, 
and thus the diff structure is close to the original.

11u webrev: http://cr.openjdk.java.net/~dchuyko/8249189/webrev.11u.00/

Testing: compiler/c2/TestSkipLongToIntCast.java, tier1, tier2.

Generated part of aarch64.ad file matches the output of 'm4 aarch64_ad.m4'.

--
Thanks,
-Dmitry