Remove ui-refresh-overrides.less and UI refresh toggle

core/src/main/java/hudson/Functions.java

@@ -188,10 +188,6 @@ public class Functions {
     private static final AtomicLong iota = new AtomicLong();
     private static Logger LOGGER = Logger.getLogger(Functions.class.getName());
 
-    @Restricted(NoExternalUse.class)
-    @SuppressFBWarnings(value = "MS_SHOULD_BE_FINAL", justification = "for script console")
-    public static /* non-final */ boolean UI_REFRESH = SystemProperties.getBoolean("jenkins.ui.refresh");
-
     public Functions() {
     }
 
@@ -520,16 +516,6 @@ public class Functions {
         return SystemProperties.getString(key);
     }
 
-    /**
-     * Returns true if and only if the UI refresh is enabled.
-     *
-     * @since 2.222
-     */
-    @Restricted(DoNotUse.class)
-    public static boolean isUiRefreshEnabled() {
-        return UI_REFRESH;
-    }
-
     public static Map getEnvVars() {
         return new TreeMap<>(EnvVars.masterEnvVars);
     }