[InstCombine] Cleanup some duplicated one use checks

Summary:
These 4 patterns have the same one use check repeated twice for each. Once without a cast and one with. But the cast has no effect on what method is called.

For the OR case I believe it is always profitable regardless of the number of uses since we'll never increase the instruction count.

For the AND case I believe it is profitable if the pair of xors has one use such that we'll get rid of it completely. Or if the C value is something freely invertible, in which case the not doesn't cost anything.

Reviewers: spatel, majnemer

Reviewed By: spatel

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D34308

llvm-svn: 305705