[PowerPC] Do not emit record-form rotates when record-form andi/andis suffices

This is a follow-up to the previous patch that eliminated some of the rotates.
With this addition, we will also emit the record-form andis.

This patch increases the number of record-form rotates we eliminate by
more than 70%.

Differential revision: https://reviews.llvm.org/D44897

llvm-svn: 342478