bpo-31803: time.clock() and time.get_clock_info('clock') now emit a
DeprecationWarning warning.
Replace time.clock() with time.perf_counter() in tests and demos.
Remove also hasattr(time, 'monotonic') in test_time since time.monotonic()
is now always available since Python 3.5.
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.
Victor Stinner
Serhiy Storchaka
Ezio Melotti
Alexander Belopolsky