Replaced hard coded 0 in total test coverage by OsBlaineOra · Pull Request #1140 · utPLSQL/utPLSQL

with covered lines / total  total lines.
Rounding to 17 decimal places since that's what I found when looking at cobertura examples online.
Used an rpad to generate the format mask to avoid having a long string of 9s.

This was mentioned in utPLSQL#1107 but does not have an issue of its own.

I introduced the error in the previous commit.

To fix I added a l_lines_valid variable, used a case statement to check for 0 else return the calculation.
I also replaced the lines_valid calculation to use the new variable to reduce code duplication.