[debugger] add test case for debug-evaluation with promise microtasks.

test/mjsunit/es6/debug-promises/evaluate-across-microtasks.js

+// Copyright 2014 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: --expose-debug-as debug --allow-natives-syntax
+
+var Debug = debug.Debug;
+var listenerComplete = false;
+var exception = null;
+var count = 0;
+var log = [];
+var done = false;
+
+function LogX(x) {
+  var stored_count = count;
+  return function() {
+    log.push(`[${stored_count}] ${x}`);
+  };
+}
+
+function DebuggerStatement() {
+  log.push(`[${count}] debugger`);
+  if (count++ < 3) {
+    debugger;
+  }
+}
+
+function listener(event, exec_state, event_data, data) {
+  if (event != Debug.DebugEvent.Break) return;
+  try {
+    var p = Promise.resolve();
+    var q = p.then(LogX("then 1"));
+    p.then(LogX("then 2"));
+    q.then(LogX("then 3"));
+    q.then(DebuggerStatement);
+    var r = q.then(() => { throw 1; });
+    r.catch(LogX("catch"));
+    listenerComplete = true;
+  } catch (e) {
+    exception = e;
+    print(e, e.stack);
+    quit(1);
+  };
+};
+
+// Add the debug event listener.
+Debug.setListener(listener);
+
+DebuggerStatement();
+LogX("start")();
+
+// Make sure that the debug event listener was invoked.
+assertTrue(listenerComplete);
+
+%RunMicrotasks();
+
+var expectation =
+  [ "[0] debugger", "[1] start", "[1] then 1",
+    "[1] then 2", "[1] then 3", "[1] debugger",
+    "[2] then 1", "[2] then 2", "[1] catch",
+    "[2] then 3", "[2] debugger", "[3] then 1",
+    "[3] then 2", "[2] catch", "[3] then 3",
+    "[3] debugger", "[3] catch",
+  ];
+
+assertEquals(expectation, log);