Fix the MUMPS coverage parser:
* Account for tabs after entry points
* Stop double incrementing lines that have explicit calls to the 0 line
* If a line has been previously marked as non executable, but then
contains a count, increment it an extra one to push it back into
the executable code set.
Add a custom routine and corresponding coverage files in the test case.
This file is smaller and has cmcov/mcov files that have data for only
that routine.