Move /src/test to /tests

tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.rs

@@ -0,0 +1,9 @@
+fn no_restriction<T>(x: &()) -> &() {
+    with_restriction::<T>(x) //~ ERROR the parameter type `T` may not live long enough
+}
+
+fn with_restriction<'b, T: 'b>(x: &'b ()) -> &'b () {
+    x
+}
+
+fn main() {}