Consistent register use for instructions with two regs and one immediate

[koute]

Currently the register usage of reg_imm2 instructions is inconsistent:

• load_* and cmov_* use r_A as the destination register
• rest of the instructions use r_B as the destination register

This PR aligns the instructions to always use r_A as the destination register (or in case of the store_* instructions as the source register).