Fix IdleNotificationFinishMarking test on slow devices.

BUG=
TBR=ulan@chromium.org

Review URL: https://codereview.chromium.org/641533004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24569 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

test/cctest/test-heap.cc

@@ -2219,8 +2219,8 @@ TEST(IdleNotificationFinishMarking) {
   }
 
   // The next idle notification has to finish incremental marking.
-  const int kShortIdleTimeInMs = 1;
-  CcTest::isolate()->IdleNotification(kShortIdleTimeInMs);
+  const int kLongIdleTime = 1000000;
+  CcTest::isolate()->IdleNotification(kLongIdleTime);
   CHECK_EQ(CcTest::heap()->gc_count(), 1);
 }