AArch64 instrtuctions with no test is implemented.

[yomaytk]

Some of the implemented aarch64 instructions have not been tested. At least the following instructions have not been tested.

USHR  <Vd>.<T>, <Vn>.<T>, #<shift>
ADC  <Xd>, <Xn>, <Xm>
UMSUBL <Xd>, <Wn>, <Wm>, <Xa>
FSUB <Vd>.<T>, <Vn>.<T>, <Vm>.<T>
FDIV  <Vd>.<T>, <Vn>.<T>, <Vm>.<T> (only 32bit or 64bit)
FCSEL  <Dd>, <Dn>, <Dm>, <cond>
UCVTF  <V><d>, <V><n> (<V> = S)
UCVTF  <V><d>, <V><n> (<V> = D)
SCVTF  <V><d>, <V><n> (<V> = S)
SCVTF  <V><d>, <V><n> (<V> = D)
FRINTA  <Dd>, <Dn>
FCVTAS  <Xd>, <Dn>