[debug] Support bigints in JS debugger test wrapper

Bug: v8:7487, v8:7486
Change-Id: I236af86639b9cec88e91af5659478206578da9e9
Reviewed-on: https://chromium-review.googlesource.com/964325Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51977}

test/debugger/debug/debug-bigint.js

+// Copyright 2018 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-bigint
+
+Debug = debug.Debug
+let exception = false;
+
+Debug.setListener(function(event, exec_state, event_data, data) {
+  if (event != Debug.DebugEvent.Break) return;
+  try {
+    const o = exec_state.frame(0).evaluate("42n", true);
+    assertEquals("bigint", o.type());
+    assertFalse(o.isUndefined());
+    assertEquals("bigint", typeof(o.value()));
+    assertEquals(42n, o.value());
+  } catch (e) {
+    exception = e;
+  };
+});
+
+!function() { debugger; }();
+assertFalse(exception, "exception in listener")

test/debugger/test-api.js

@@ -641,6 +641,12 @@ class DebugWrapper {
         }
         break;
       }
+      case "bigint": {
+        assertEquals("n", obj.unserializableValue.charAt(
+            obj.unserializableValue.length - 1));
+        value = eval(obj.unserializableValue);
+        break;
+      }
       case "string":
       case "boolean": {
         break;