Coverage analysis done using "forced" encoder and decoder modes

The coverage analysis includes the test cases in self_test.prm and self_test_evs.prm, which include "mode forcing" both in the encoder and decoder. For instance, there are a few TD/DFT stereo modes forced in self_test.prm, speech/music mode forced in self_test_evs.prm and -force_subframe_bin in self_test.prm.

These options will be cleaned out when running the complexity analysis, so there is a risk that some parts are not covered there. Further, I suppose these options will not be in the final code, so it is good to detect if we have missing coverage already now and possibly tweak the test vectors to increase coverage.