Remove structural equiv check for Array const.

Author: jumbatm

src/librustc_lint/builtin.rs

@@ -2254,9 +2254,6 @@ impl ClashingExternDeclarations {
                             (Array(a_ty, a_const), Array(b_ty, b_const)) => {
                                 // For arrays, we also check the constness of the type.
                                 a_const.val == b_const.val
-                                    && structurally_same_type_impl(
-                                        seen_types, cx, a_const.ty, b_const.ty, ckind,
-                                    )
                                     && structurally_same_type_impl(
                                         seen_types, cx, a_ty, b_ty, ckind,
                                     )