[NewPM] -print-module-scope -print-after now prints module even after invalidated Loop/SCC

-print-after IR printing generally can not print the IR unit (Loop or SCC)
which has just been invalidated by the pass. However, when working in -print-module-scope
mode even if Loop was invalidated there is still a valid module that we can print.

Since we can not access invalidated IR unit from AfterPassInvalidated instrumentation
point we can remember the module to be printed *before* pass. This change introduces
BeforePass instrumentation that stores all the information required for module printing
into the stack and then after pass (in AfterPassInvalidated) just print whatever
has been placed on stack.

Reviewed By: philip.pfaffe
Differential Revision: https://reviews.llvm.org/D55278

llvm-svn: 349896