Remove --harmony-async-await runtime flag

test/debugger/debug/es8/async-debug-caught-exception-cases.js

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --harmony-async-await
-
 Debug = debug.Debug
 
 let events = 0;
 
 function listener(event, exec_state, event_data, data) {
   if (event != Debug.DebugEvent.Exception) return;
   events++;
 }
 
 async function thrower() {
@@ skipping 189 matching lines @@
       Debug.clearBreakOnException();
     } else {
       Debug.clearBreakOnUncaughtException();
     }
     if (expectedEvents != events) {
       %AbortJS(`producer ${producer} consumer ${consumer} expectedEvents ` +
                `${expectedEvents} caught ${caught} events ${events}`);
     }
   }
 }