tests/src.ctf.fs/test_fail: test with both autodiscovery and explicit component insta...

tests/src.ctf.fs/test_fail: test with both autodiscovery and explicit component instantiation

Specifying a path to a failing trace like this:

  babeltrace2 mytrace

vs

  babeltrace2 -c src.ctf.fs -p 'inputs=["mytrace"]'

... exercises different code paths.  If the failure is due to bad
metadata, the first one will error out during the support-info query
phrase, whereas the second one will error out in the component
initialization.  I think it would be good to exercise both in the test
with failing traces.

Rename the test_fail function to test_fail_method, and add a parameter
indicating which method of passing the trace path to use (autodisc vs
component).  Add a new test_fail function that tries with both methods.

Change-Id: Ieb65504a773b0915946f8ef543a7d0930ca0a7d7
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Reviewed-on: https://review.lttng.org/c/babeltrace/+/12750
Reviewed-by: Philippe Proulx <eeppeliteloop@gmail.com>