Fix cycle dependency in sp-runtime-interface (#4353)

* Fix cycle dependency in `sp-runtime-interface`

* Fixes tests

substrate/primitives/runtime-interface/tests/ui.rs

@@ -0,0 +1,27 @@
+// Copyright 2019 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+use std::env;
+
+#[rustversion::attr(not(stable), ignore)]
+#[test]
+fn ui() {
+	// As trybuild is using `cargo check`, we don't need the real WASM binaries.
+	env::set_var("BUILD_DUMMY_WASM_BINARY", "1");
+
+	let t = trybuild::TestCases::new();
+	t.compile_fail("tests/ui/*.rs");
+}