This patch handles sinking a replicate region after another replicate region. In that case, we can connect the sink region after the target region. This properly handles the case for which an assertion has been added in 337d7652823f. Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=34842. Reviewed By: Ayal Differential Revision: https://reviews.llvm.org/D103514