- Define test_utils_interactive_sync as DEFAULT_MODULE in Makefile.tests_common
- For tests disabling autoinit, add test_utils_interactive_sync to main
- Add DISABLE_MODULE += test_utils_interactive_sync for tests requiring
sudo, `tests/shell`, `tests/minimal` and `tests/stdin`
- Add shell_commands to tests/periph_wdt and tests/struct_tm_utility to
pull `r` and `s` commands
- Remove includes and usage in `tests/main.c` for tests that where
already using test_utils_interactive_sync
As with #7816: testing timings over the UART doesn't make much sense.
This PR removes those timer testing in `pexpect` for
`tests/xtimer_usleep` and simplifies and cleans-up a lot of code overall
(converting counting while-loops to for-loops, syncing iterations of
the test etc.)
