Ensure that the counter unit of measurement, "c", is parsed correctly
for performance data values again.
A prior refactoring in 720a88c29a changed
the parsing logic, resulting in an incorrect behavior for counter units.
By passing the raw input into the l_CsUoMs map first, the "c" UoM is
removed. Moving the explicit counter check before passing the raw unit
into the map resolves this issue.
Fixes#9540.
7e65a60a5d