target-arm: A64: Implement remaining non-pairwise int SIMD 3-reg-same insns

target-arm: A64: Implement remaining non-pairwise int SIMD 3-reg-same insns

Implement the SIMD 3-reg-same instructions where the size == 3 case
is reserved: SHADD, UHADD, SRHADD, URHADD, SHSUB, UHSUB, SMAX,
UMAX, SMIN, UMIN, SABD, UABD, SABA, UABA, MLA, MLS, MUL, PMUL,
SQRDMULH, SQDMULH. (None of these have scalar-3-same versions.)
This completes the non-pairwise integer instructions in this category.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>