[ARM] Add support for ORR and ORN instruction substitutions
Recently support was added for substituting one intruction for another by
negating or inverting the immediate, but ORR and ORN were missed so this patch
This one is slightly different to the others in that ORN only exists in thumb,
so we only do the substitution in thumb.
Differential Revision: https://reviews.llvm.org/D32534