Upgrade V8 to 5.1.281.57  DO NOT MERGE

FPIIM-449

Change-Id: Id981b686b4d587ac31697662eb98bb34be42ad90
(cherry picked from commit 3b9bc31999c9787eb726ecdbfd5796bfdec32a18)
diff --git a/test/mjsunit/debug-step-end-of-script.js b/test/mjsunit/debug-step-end-of-script.js
index ded58d1..e8ffcc8 100644
--- a/test/mjsunit/debug-step-end-of-script.js
+++ b/test/mjsunit/debug-step-end-of-script.js
@@ -5,7 +5,7 @@
 // Flags: --expose-debug-as debug --allow-natives-syntax
 
 var Debug = debug.Debug;
-var expected = ["debugger;", "", "debugger;"];
+var expected = ["debugger;", "debugger;"];
 
 function listener(event, exec_state, event_data, data) {
   if (event != Debug.DebugEvent.Break) return;