[PatternMatch] Big mechanical rename OwningRewritePatternList ->...

[PatternMatch] Big mechanical rename OwningRewritePatternList -> RewritePatternSet and insert -> add.  NFC

This doesn't change APIs, this just cleans up the many in-tree uses of these
names to use the new preferred names.  We'll keep the old names around for a
couple weeks to help transitions.

Differential Revision: https://reviews.llvm.org/D99127