Install a tracing subscriber in the test process itself, routed through the
libtest capture, so diagnostics from in-process library code show up alongside
a failing test's output instead of being discarded.
Have the tsa test helper fetch shaping at Error level so a failed HTTP
fetch fails the test with the real reason, rather than being downgraded
to an empty result that caused the tsa_basic_automation test to fail.
Wez Furlong
bd0ef3f530