Fix a crash.
The PRNG is not guaranteed to make the same output given the same seed. Remove redundant random_seed().
Calendar.YMD: Improved dwim_time().

dwim-time() now knows about ISO 9601 timestamps with colons.

Fixes [roxen.com #23993].
Small cleanup of find_testsuites. module_testsuite no longer supported as test file name.
Make cast() protected.
cast tests.
pgsql: Improve backtraces in debugging mode.