[NewPM] Introduce PreserveCFG check

Check that all passes, which report they preserve CFG,
are really preserving CFG.
A new standard instrumentation is introduced. It can be
switched on/off by the flag verify-cfg-preserved, which
is on by default for debug builds.

Reviewers: kuhar, fedor.sergeev

Differential Revision: https://reviews.llvm.org/D81558