suite: output tally if suite is skipped

If the 'tally' option is given to a suite, and so is the 'skip' option
(meaning skip all tests in this suite but also print a tally), then
print a tally showing that all tests were skipped.
run-file: failing test

The problem seems to be that I can't redefine an already-defined
procedure 'call-with-input-file' to mock its behaviour.