remove trivial goals from sessions

examples/foveoos11-cm/duplets/why3session.xml

examples/foveoos11-cm/duplets/why3shapes.gz

examples/hackers-delight/why3session.xml

examples/hackers-delight/why3shapes.gz

examples/hillel_challenge/why3session.xml

examples/hillel_challenge/why3shapes.gz

examples/inverse_in_place/why3session.xml

examples/inverse_in_place/why3shapes.gz

examples/leftist_heap/why3session.xml

examples/leftist_heap/why3shapes.gz

examples/linear_probing/why3session.xml

examples/linear_probing/why3shapes.gz

examples/linked_list_rev/why3session.xml

examples/linked_list_rev/why3shapes.gz

examples/max_matrix/why3session.xml

examples/max_matrix/why3shapes.gz

examples/multiprecision/lineardecision/why3session.xml

examples/multiprecision/lineardecision/why3shapes.gz

examples/multiprecision/toom/why3session.xml

examples/multiprecision/toom/why3shapes.gz