llvm control deps: fix computing DFLocal
llvm control deps: fix computing DFLocal

we checked for wrong immediate post-dominator

Signed-off-by: Marek Chalupa <a05df156a69ad59faa9af9b666ef78009594c145@gmail.com>

mchalupa/dg,mchalupa/dg,mchalupa/dg,mchalupa/dg