Fix the test coverage (test svd and regularization)

[tyronerees]

The two major ones have been fixed. Still outstanding:

• [x] model=1, type_of_method=2, reg_order<=0
• [ ] hit max_tr_reductions?
• [ ] hit x_no_progress?
• [ ] aint_tr: solve hard case for model /= 1
• [ ] more_sorensen: hit the case where sigma not tiny and we aren't on the tr radius
• [ ] more_sorensen: hit the case where a shift is needed
• [ ] solve_galahad: hit the tiny cases for v_trans and ew
• [ ] solve_galahad: hit the case where J'J + Delta/2 I is not spd
• [ ] update_trust_region_radius: test behaviour with NaNs
• [ ] Newton-tensor code