[analyzer] Move ReturnStmt retain-count analysis from CFRefCount to RetainReleaseChecker. Tweak CFRefReport to reflect that fact that ReturnStmt checks are pre-statement, not post-statement.  No intended functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@138358 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed