test: Add a test case that ensures ret &EXPR works.

Author: pcwalton

src/test/run-pass/regions-addr-of-ret.rs

@@ -0,0 +1,8 @@
+fn f(x : &a.int) -> &a.int {
+    ret &*x;
+}
+
+fn main() {
+    log(error, #fmt("%d", *f(&3)));
+}
+