gimple: Handle variable-sized vectors in BIT_FIELD_REF

gimple: Handle variable-sized vectors in BIT_FIELD_REF

Handle variable-sized vectors for BIT_FIELD_REF canonicalization.

gcc/ChangeLog:

	* gimple-fold.cc (maybe_canonicalize_mem_ref_addr): Handle variable
	sized vector types in BIT_FIELD_REF canonicalization.
	* tree-cfg.cc (verify_types_in_gimple_reference): Change object-size-
	checking for BIT_FIELD_REF to error offsets that are known_gt to be
	outside object-size.  Out-of-range offsets can happen in the case of
	indices that reference VLA SVE vector elements that may be outside the
	minimum vector size range and therefore maybe_gt is not appropirate
	here.