[InstCombine] Add tests for cases where we don't recognize type promoted rotate idioms.

These rotates take the form

(x << (n & mask)) | (x >> (-n & mask)) where mask is bitwidth - 1.

If x has been promoted to a wider type than its original bit width due to type promotion we fail to narrower it and therefore don't recognize it as a rotate.

llvm-svn: 332068