Optimize floats memset for zero initialization

[rafaelsamenezes]

As shown in #1508 esbmc can't handle float memset properly as it breaks k-induction for some reason. This PR is just a workaround by enabling an extra simplification for the case of float f; memset(&f, 0, sizeof(float));

[lucasccordeiro]

@rafaelsamenezes: could you also add a regression test that gives "VERIFICATION SUCCESSFUL"?

[rafaelsamenezes]

Results (30s):

Statistics:          23805 Files
  correct:           14433
    correct true:     8013
    correct false:    6420
  incorrect:            64
    incorrect true:     14
    incorrect false:    50
  unknown:            9308
  Score:             21198 (max: 38482)

It solves a few extra cases.

[fbrausse]

LGTM. @rafaelsamenezes are these numbers for svcomp main branch or svcomp23 or which ones? Could you add the link?

[lucasccordeiro]

Thanks for submitting this PR, @rafaelsamenezes.