Fix fallout in tests.

Author: jseyfried

src/test/parse-fail/circular_modules_hello.rs

@@ -12,6 +12,7 @@
 
 // ignore-test: this is an auxiliary file for circular-modules-main.rs
 
+#[path = "circular_modules_main.rs"]
 mod circular_modules_main;
 
 pub fn say_hello() {