[arm][arm64] Improve CountTrailingZero implementation.

src/compiler/arm64/instruction-codes-arm64.h

Index: src/compiler/arm64/instruction-codes-arm64.h
diff --git a/src/compiler/arm64/instruction-codes-arm64.h b/src/compiler/arm64/instruction-codes-arm64.h
index acf7a4fdc05d54ec8f5e8f5ee5f156d3e21f0614..f03c2fb436fe5041c33a88a4f4e00d707dfeee5d 100644
--- a/src/compiler/arm64/instruction-codes-arm64.h
+++ b/src/compiler/arm64/instruction-codes-arm64.h
@@ -73,6 +73,8 @@ namespace compiler {
   V(Arm64Ubfx32)                   \
   V(Arm64Ubfiz32)                  \
   V(Arm64Bfi)                      \
+  V(Arm64Rbit)                     \
+  V(Arm64Rbit32)                   \
   V(Arm64TestAndBranch32)          \
   V(Arm64TestAndBranch)            \
   V(Arm64CompareAndBranch32)       \
@@ -149,7 +151,6 @@ namespace compiler {
   V(Arm64Ldr)                      \
   V(Arm64Str)
 
-
 // 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