Move "active" code out of debug statements

Move "active" code out of debug statements

Certain g_assert() statements contained expressions that modify the rest of
the program state (eg. modifying variables). As stated in the GLib reference,
g_assert() is a macro that can be compiled out. This would change the behavior
of an otherwise correct lttv.

Signed-off-by: Benjamin Poirier <benjamin.poirier@polymtl.ca>