Tests: Use Perl prove as the testsuite runner

Tests: Use Perl prove as the testsuite runner

This commit modify the make check target to run Perl prove as the
testsuite runner.

$ cd babeltrace/tests
$ ./run.sh tests

One can also run tests manually using prove:

$ prove --exec '' path/to/test

    OR

$ prove --exec '' - < testlist

Signed-off-by: Christian Babeux <christian.babeux@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>