conditions when regrtest is run with its -j option.

for extension modules on Windows.

Thanks to Eric Snow for helping with imp.load_module() (previous
commit) which led to the removal of a bunch of C code.

Issue #14589: Update certificate chain for sha256.tbs-internet.com, fixing a test failure in test_ssl.

Issue #14589: Update certificate chain for sha256.tbs-internet.com, fixing a test failure in test_ssl.

__loader__.

Since import now sets __loader__ on all modules it creates and
imp.reload() already relied on the attribute for modules that import
didn't create, the only potential compatibility issue is if people
were deleting the attribute on modules and expecting imp.reload() to
continue to work.