re PR tree-optimization/51074 (No constant folding performed for VEC_PERM_EXPR, VEC_INTERLEAVE*EXPR, VEC_EXTRACT*EXPR)

	PR tree-optimization/51074
	* fold-const.c (fold_binary_loc): Fix up VEC_INTERLEAVE_*_EXPR
	handling for BYTES_BIG_ENDIAN.
	* optabs.c (can_vec_perm_for_code_p): Likewise.

	* gcc.dg/vect/pr51074.c: New test.

From-SVN: r181627