Better codegen of binary integer ops with 32 bit immediate operands.

Better codegen of binary integer ops with 32 bit immediate operands.
This transformation fires a few dozen times across the testsuite.

For example, int test2(int X) { return X ^ 0x0FF00FF0; }
Old:
_test2:
        lis r2, 4080
        ori r2, r2, 4080
        xor r3, r3, r2
        blr

New:
_test2:
        xoris r3, r3, 4080
        xori r3, r3, 4080
        blr

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17004 91177308-0d34-0410-b5e6-96231b3b80d8