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/declare-locally.js b/test/mjsunit/declare-locally.js
index 45d30e0..f03217e 100644
--- a/test/mjsunit/declare-locally.js
+++ b/test/mjsunit/declare-locally.js
@@ -27,19 +27,13 @@
 
 // Make sure that we're not overwriting global
 // properties defined in the prototype chain too
-// early when shadowing them with var/const
+// early when shadowing them with var
 // declarations.
 
 // This exercises the code in runtime.cc in
 // DeclareGlobal...Locally().
 
-// Flags: --legacy-const
-
 this.__proto__.foo = 42;
-this.__proto__.bar = 87;
 
 eval("assertEquals(undefined, foo); var foo = 87;");
 assertEquals(87, foo);
-
-eval("assertEquals(undefined, bar); const bar = 42;");
-assertEquals(42, bar);