tests: improve shell output readability

tests: improve shell output readability

Modify the test traces to include the file name in addition to the
function and line name. It makes it easier to locate the faulty line
without going back to the test name.

Format the trace lines to be emacs friendly (filename:lineno) so that
C-x ` or C-c C-c jumps to the right file and the right line when running
the test with M-x compile.

Signed-off-by: Loic Dachary <ldachary@redhat.com>