Try all stable candidates first before trying unstable ones

compiler/rustc_interface/src/tests.rs

@@ -751,6 +751,7 @@ fn test_debugging_options_tracking_hash() {
     tracked!(panic_abort_tests, true);
     tracked!(panic_in_drop, PanicStrategy::Abort);
     tracked!(partially_uninit_const_threshold, Some(123));
+    tracked!(pick_stable_methods_before_any_unstable, false);
     tracked!(plt, Some(true));
     tracked!(polonius, true);
     tracked!(precise_enum_drop_elaboration, false);