Move /src/test to /tests

tests/rustdoc-ui/failed-doctest-missing-codes.rs

@@ -0,0 +1,12 @@
+// FIXME: if/when the output of the test harness can be tested on its own, this test should be
+// adapted to use that, and that normalize line can go away
+
+// compile-flags:--test
+// normalize-stdout-test: "src/test/rustdoc-ui" -> "$$DIR"
+// normalize-stdout-test "finished in \d+\.\d+s" -> "finished in $$TIME"
+// failure-status: 101
+
+/// ```compile_fail,E0004
+/// let x: () = 5i32;
+/// ```
+pub struct Foo;