When running all the system tests, output from a test is sent to a
test.output file in the test directory. These are combined in to
systests.output when the run finishes.
(cherry picked from commit 055e5be9fd)
Miscellaneous tidying up of run management. The most significant
change is that "runall.sh" now runs _all_ the tests, even the
ones that can run in parallel. runsequential.sh is the script
to run tests that have not been converted to parallel running.
(cherry picked from commit 32fe6f7682)
