Upgrade V8 to 5.1.281.57  DO NOT MERGE

FPIIM-449

Change-Id: Id981b686b4d587ac31697662eb98bb34be42ad90
(cherry picked from commit 3b9bc31999c9787eb726ecdbfd5796bfdec32a18)
diff --git a/test/cctest/test-hashing.cc b/test/cctest/test-hashing.cc
index 25a8e5c..d6f055e 100644
--- a/test/cctest/test-hashing.cc
+++ b/test/cctest/test-hashing.cc
@@ -90,6 +90,15 @@
   __ pop(kRootRegister);
   __ jr(ra);
   __ nop();
+#elif V8_TARGET_ARCH_S390
+  __ push(kRootRegister);
+  __ push(ip);
+  __ InitializeRootRegister();
+  __ lhi(r2, Operand(key));
+  __ GetNumberHash(r2, ip);
+  __ pop(ip);
+  __ pop(kRootRegister);
+  __ Ret();
 #elif V8_TARGET_ARCH_PPC
   __ function_descriptor();
   __ push(kRootRegister);