Stabilise lunar-phase-list test (bug#45818)

Stabilise lunar-phase-list test (bug#45818)

The test reference data was produced with accidental interference from
the system daylight saving in effect at the time.  Prevent that
from occurring again and correct the data.

* test/lisp/calendar/lunar-tests.el (with-lunar-test):
Switch to UTC and make sure daylight saving adjustment is disabled.
Use normal time presentation for maintainability.
* test/lisp/calendar/lunar-tests.el (lunar-test-phase): Adjust to UTC.
(lunar-test-phase-list): Adjust to UTC with correct times.
Enable the test by removing its :unstable mark.