[11] RFR(XS): 8205341: AARCH64: Clean up duplicate uzp1 & uzp2 instruction definition

[Dmitry Chuyko]

Hello,

Please review a small fix for aarch64 instructions encoding. The fix 
removes duplicate definition of two instructions from 
assembler_aarch64.hpp. The only usage of that variant was in 
MacroAssembler::kernel_crc32 in case of -UseCRC32 +UseNeon. I changed it 
to use another definition and made testing comparing checksums for that 
case.

rfe: https://bugs.openjdk.java.net/browse/JDK-8205341
webrev: http://cr.openjdk.java.net/~dchuyko/8205341/webrev.00/

-Dmitry