test(fix): make the fullcoverage test work on 3.11
test(fix): make the fullcoverage test work on 3.11

It didn't work because the os module is frozen on 3.11, so it gets no
measurement.  Use -X to disable the frozen modules feature for the test.

nedbat/coveragepy,nedbat/coveragepy,nedbat/coveragepy,nedbat/coveragepy,nedbat/coveragepy