[StandardInstrumentations] Verify function doesn't change if analyses are preserved

Reuse StructuralHash and allow it to be used in non-expensive checks builds.

Move PreservedAnalysisChecker further down StandardInstrumentations so other Instrumentations (e.g. printing) have a chance to run before PreservedAnalysisChecker crashes.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D146003