fileset: restrict getfileset() to not return a computed set (API)
And rename the functions accordingly. fileset.match() will be changed to
not compute the initial subset.
test-glog*.t get back to the state before 9f9ffe5f687c "match: compose
'set:' pattern as matcher."
#
# Avoid interference from actual test env:
unset HGTEST_JOBS
unset HGTEST_TIMEOUT
unset HGTEST_PORT
unset HGTEST_SHELL