Remove code in vectorizer pattern recog relying on vec_cond{u,eq,}

Remove code in vectorizer pattern recog relying on vec_cond{u,eq,}

With the intent to rely on vec_cond_mask and vec_cmp patterns
comparisons do not need rewriting into COND_EXPRs that eventually
combine to vec_cond{u,eq,}.

	* tree-vect-patterns.cc (check_bool_pattern): For comparisons
	we do nothing if we can expand them or we can't replace them
	with a ? -1 : 0 condition - but the latter would require
	expanding the comparison which we proved we can't.  So do
	nothing, aka not think vec_cond{u,eq,} will save us.