requires them.  Disable executable bits and shebang lines in test and
benchmark files in order to prevent using a random system python, and in
source files of modules which don't provide command line interface.  Fixed
shebang line to use python3 executable in the unittestgui script.

instead of manually listing tests for test.support.run_unittest().

other threads.

Fix #13449: add 'blocking' parameter to sched.scheduler.run() so that the scheduler can be used in non-blocking applications

sched.py: fix test_queue by making sure that queue property returns an orderd list of upcoming events

sched.scheduler class constructor's timefunc and delayfunct parameters are now optional.
scheduler.enter and scheduler.enterabs methods gained a new kwargs parameter.

Patch contributed by Matt Mulsow.