jjb: Use `**/*.log` to glob TAP log files

jjb: Use `**/*.log` to glob TAP log files

`**/*.*` catches other files left when running with more verbose test
configurations. `*.log` is the suffix for automake test log files[1].

See this proposed patch to lttng-tools master[2] which updates the log
suffix for the additional verbose log files.

[1]: https://www.gnu.org/software/automake/manual/html_node/Parallel-Test-Harness.html
[2]: https://review.lttng.org/c/lttng-tools/+/13430

Change-Id: If50a775af193a2973fd35b2b56337be21791fcc0
Signed-off-by: Kienan Stewart <kstewart@efficios.com>