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-codes-x64.h b/src/compiler/x64/instruction-codes-x64.h
index 6d5e77c..bd19386 100644
--- a/src/compiler/x64/instruction-codes-x64.h
+++ b/src/compiler/x64/instruction-codes-x64.h
@@ -18,8 +18,12 @@
   V(X64And32)                      \
   V(X64Cmp)                        \
   V(X64Cmp32)                      \
+  V(X64Cmp16)                      \
+  V(X64Cmp8)                       \
   V(X64Test)                       \
   V(X64Test32)                     \
+  V(X64Test16)                     \
+  V(X64Test8)                      \
   V(X64Or)                         \
   V(X64Or32)                       \
   V(X64Xor)                        \
@@ -139,7 +143,6 @@
   V(X64Poke)                       \
   V(X64StackCheck)
 
-
 // Addressing modes represent the "shape" of inputs to an instruction.
 // Many instructions support multiple addressing modes. Addressing modes
 // are encoded into the InstructionCode of the instruction and tell the