Fix correct warning with c engine when skipping lines
Fixed bug where c engine would not print warnings for lines
it skipped in case the skipped line had an inline comment.
Also, its accounting of number of fields in such lines would
be off by one.

 - [x] closes #16472 
 - [x] tests added
 - [x] tests passed
 - [x] passes ``git diff upstream/master --name-only -- '*.py' | flake8 --diff``
 - [x] whatsnew entry
