thorium: time in tracepoints is implicit

Link: https://github.com/GeneAssembly/biosal/issues/759
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
thorium: add THORIUM_USE_LTTNG

Link: https://github.com/GeneAssembly/biosal/issues/758
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>