[analyzer] Rename PruneNullReturnPaths to SuppressNullReturnPaths.

"Prune" is the term for eliminating pieces of a path that are not
relevant to the user. "Suppress" means don't show that path at all.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173544 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed