apply TLC to GIMPLE reference verification

This inlines verify_types_in_gimple_min_lval and makes sure we
also verify call lhs and arguments.  It also asserts that
WITH_SIZE_EXPR in plain assignments does not happen, instead
those should have become memcpy/memset.

2021-05-18  Richard Biener  <rguenther@suse.de>

	* tree-cfg.c (verify_types_in_gimple_min_lval): Inline...
	(verify_types_in_gimple_reference): ... here.  Sanitize.
	(verify_gimple_call): Verify references in LHS and arguments.
	(verify_gimple_assign_single): Reject WITH_SIZE_EXPR.