Introduce unary and binary versions of the branch instruction. This will give more ISA_OPC_BRANCH_XXX opcodes to work with. This helps to get rid of these 'maybe' bitsets and is needed for the assembler. Signed-off-by: Christian Gmeiner <cgmeiner@igalia.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30030>