[TableGen][GlobalISel] Add specialized opcodes (#74823)

Most users of AddImm and CheckConstantInt only use 1 byte immediates, so
I added an opcode variants for those. That way all those instructions
save 7 bytes.
Also added an opcode for AddTempRegister for the cases where there are
no register flags.

Space savings:
    - AMDGPUGenGlobalISel: 470180 bytes to 422564 (-10%)
    - AArch64GenGlobalISel.inc: 383893 bytes to 374046