Use GetPointerUnchecked in how, pre-checked areas.
armjit: Optimize out a few immediate logic cases.
armjit: Reverse add t0, N, t1 to preserve imm.
armjit: Optimize movz/movn with immediates.
armjit: Avoid flushing imm on add t0, imm, imm.
armjit: Preserve immediates more in nor.
armjit: Preserve imms in slt/sltu as possible.
armjit: Use a MOV for add/or with 0.

Might skip the ALU, so might be faster.
Merge pull request #4479 from unknownbrackets/perf

Small optimizations (armjit) for imms