lttng-tools: filter random filename of ptest output

lttng-tools: filter random filename of ptest output

When run the ptest of lttng-tools, it produced many random filename
when the tests passed, the output confused QA analysis, so we need
to filter the ptest output if tests passed and add up the passed and
failed tests.

NOTE:The tests invoked the run.sh twice, so it output like this:
...
FAIL:...
unit_tests statistics
total pass: 133 tests passed!
total fail: 5 tests failed!
...
FAIL:...
fast_regression statistics
total pass: 1904 tests passed!
total fail: 202 tests failed!

Signed-off-by: Dengke Du <dengke.du@windriver.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>