Created by: joshua-warburton
This patch adds the appropriate macros, tests and codec entries to encode the following variants:
CNT <Zd>.<Ts>, <Pg>/M, <Zn>.<Ts>
CNTB <Xd>{, <pattern>{, MUL #<imm>}}
DECB <Xdn>{, <pattern>{, MUL #<imm>}}
DECD <Xdn>{, <pattern>{, MUL #<imm>}}
DECD <Zdn>.D{, <pattern>{, MUL #<imm>}}
DECH <Xdn>{, <pattern>{, MUL #<imm>}}
DECH <Zdn>.H{, <pattern>{, MUL #<imm>}}
SQDECH <Xdn>, <Wdn>{, <pattern>{, MUL #<imm>}}
SQDECH <Xdn>{, <pattern>{, MUL #<imm>}}
SQDECH <Zdn>.H{, <pattern>{, MUL #<imm>}}issues: #3044