try to debug a hang on the FreeBSD 9 buildbot.
Run also eintr_tester.py with python "-u" command line option to try to get the
full output on hang/crash.
"./python -m test -W test_eintr" wrote Lib/test/eintrdata/eintr_tester.py
output to stdout which was not expected.
Since test_eintr doesn't hang anymore, remove the verbose mode instead.
Skip test_open() and test_os_open(): both tests uses a FIFO and signals, but
there is a bug in the FreeBSD kernel which blocks the test. Skip the tests
until the bug is fixed in FreeBSD kernel.
Remove also debug traces from test_eintr:
* stop using faulthandler to have a timeout
* remove print()
Write also open and close on two lines in test_open() and test_os_open()
tests. If these tests block again, we can know if the test is stuck at open or
close.
test_eintr: don't always run the test in debug mode.
* Add verbose mode to test_eintr
* Always enable verbose mode in test_eintr
* Use faulthandler.dump_traceback_later() with a timeout of 15 minutes in
eintr_tester.py
