Added check if there are regions that do not implement the RegionBranchOpInterface.

Add a check if regions do not implement the RegionBranchOpInterface. This is not
allowed in the current deallocation steps. Furthermore, we handle edge-cases,
where a single region is attached and the parent operation has no results.

This fixes: https://bugs.llvm.org/show_bug.cgi?id=48575

Differential Revision: https://reviews.llvm.org/D94586