Fix pass return status for loop extractor

As loop extractor has a dependency on another pass (namely BreakCriticalEdges)
that may update the IR, use the getAnalysis version introduced in
55fe7b79 to carry that change.

Add an assert in getAnalysisID to make sure no other changed status is missed -
according to validation this was the only one.

Related to https://reviews.llvm.org/D80916

Differential Revision: https://reviews.llvm.org/D81236