Adjust time/date/cp commands in tests for portability

These changes are required to support NetBSD.
1) Use standard -p option for time command in test17.35 instead of
GNU specific format string to fetch the elapsed (real) time.

2) Adjust date command calls in test22.1 to use short option
(--date -> -d), and move options before arguments. NetBSD,
unlike Linux, disallow non standard order.

3) Use standard -R option instead of -r for cp command in test30.1.