Migrate to trybuild from compiletest

This migrates our UI tests to the recently published `trybuild` crate
which should hopefully be a bit more robust than `compiletest` over
time!

crates/macro/ui-tests/attribute-fails-to-parse.rs

@@ -1,8 +1,6 @@
-#![crate_type = "rlib"]
-
-extern crate wasm_bindgen;
-
 use wasm_bindgen::prelude::*;
 
 #[wasm_bindgen(nonsense)]
 pub fn foo() {}
+
+fn main() {}