Both tools never had safeguard checks for the options provided, and it
was possible to make pg_test_fsync run an infinite amount of time or
pass down buggy values to pg_test_timing.

These behaviors have existed for a long time, with no actual complaints,
so no backpatch is done.  Basic TAP tests are introduced for both tools.

Author: Michael Paquier
Reviewed-by: Peter Eisentraut
Discussion: https://postgr.es/m/20200806062759.GE16470@paquier.xyz