Tests defs: do not print message "Running test $0" anymore.

Tests defs: do not print message "Running test $0" anymore.

* tests/defs.in: Printing the message "=== Running test $0" at
the beginning of each tests made sense when Automake used the old
test-driver, which sent all the output directly to stdout/stderr.
Now that the parallel test-driver is used, which saves output of
each test in its correspoding log file, that old message is just
useless noise.