remove debug messages for seed merging

Signed-off-by: Sébastien Boisvert <sebastien.boisvert.3@ulaval.ca>
sort seeds by length

Signed-off-by: Sébastien Boisvert <sebastien.boisvert.3@ulaval.ca>
fetch coverage data for seed paths

Signed-off-by: Sébastien Boisvert <sebastien.boisvert.3@ulaval.ca>