Fix IdleNotificationFinishMarking test on slow devices.

test/cctest/test-heap.cc

Index: test/cctest/test-heap.cc
diff --git a/test/cctest/test-heap.cc b/test/cctest/test-heap.cc
index 969fd8824d2b20ed76bac324a4a91d8535af9b21..e2c2ca607c6ad45ca2ec0e2d7888fc55c957a98a 100644
--- a/test/cctest/test-heap.cc
+++ b/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);
 }