test___monkey_patching.py: don't fail if no tests are available for this version
fix #423: pool: LoopExit in imap/imap_unordered

It was possible for IMap/IMapUnordered greenlets to exit without putting the final StopIteration. So, whoever was waiting on the results would have to wait forever (or until LoopExit if there's nothing else running in the program).

Original patch and test by @thinxer (close #424).

Fix #311: same issue.
Event: add dummy _reset_internal_locks
util.py: remove unused variable SLEEP
test__socket_dns.py: do not compare IPv6 addresses
core.ppyx: enable check watchers
disable test_urllib2net.OtherNetworkTest.test_ftp

too slow
test___monkey_patching: set timeout to 120s
test__threadpool.py: increase expected kill.elapsed

To prevent this:

======================================================================
FAIL: test_terminate (__main__.TestPool10)
----------------------------------------------------------------------

Traceback (most recent call last):

File "test__threadpool.py", line 176, in test_terminate

assert kill.elapsed < 0.5, kill.elapsed

AssertionError: 0.564028263092041
greentest.py: do gc.collect() x 3
backport testrunner from master branch