Add testcase I meant to add in 9ee3475e09.

src/test/run-pass/type-in-nested-module.rs

@@ -0,0 +1,11 @@
+mod a {
+  mod b {
+  type t = int;
+  fn foo() {
+    let t x = 10;
+  }
+  }
+}
+
+fn main() {
+}