Upgrade V8 to 5.1.281.57  DO NOT MERGE

FPIIM-449

Change-Id: Id981b686b4d587ac31697662eb98bb34be42ad90
(cherry picked from commit 3b9bc31999c9787eb726ecdbfd5796bfdec32a18)
diff --git a/src/compiler/x64/instruction-scheduler-x64.cc b/src/compiler/x64/instruction-scheduler-x64.cc
index 1f10b51..3c31965 100644
--- a/src/compiler/x64/instruction-scheduler-x64.cc
+++ b/src/compiler/x64/instruction-scheduler-x64.cc
@@ -20,8 +20,12 @@
     case kX64And32:
     case kX64Cmp:
     case kX64Cmp32:
+    case kX64Cmp16:
+    case kX64Cmp8:
     case kX64Test:
     case kX64Test32:
+    case kX64Test16:
+    case kX64Test8:
     case kX64Or:
     case kX64Or32:
     case kX64Xor: