[NewPM] Fix -print-changed when a -filter-print-funcs function is removed

-filter-print-funcs -print-changed was crashing after the filter func
was removed by a pass with
  Assertion failed: After.find("*** IR Dump") == 0 && "Unexpected banner format."
We weren't printing the banner because when we have -filter-print-funcs,
we print each function separately, letting the print function filter out
unwanted functions.

Reviewed By: jamieschmeiser

Differential Revision: https://reviews.llvm.org/D100237