[arm][arm64] Improve CountTrailingZero implementation.

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

Index: src/compiler/arm/instruction-codes-arm.h
diff --git a/src/compiler/arm/instruction-codes-arm.h b/src/compiler/arm/instruction-codes-arm.h
index fe63fb195d4885e502c31ae242fd60e2713f7e65..0b48ef7ac765b68781dc4f3231f423d94630a68b 100644
--- a/src/compiler/arm/instruction-codes-arm.h
+++ b/src/compiler/arm/instruction-codes-arm.h
@@ -43,6 +43,7 @@ namespace compiler {
   V(ArmUxtb)                       \
   V(ArmUxth)                       \
   V(ArmUxtab)                      \
+  V(ArmRbit)                       \
   V(ArmUxtah)                      \
   V(ArmVcmpF32)                    \
   V(ArmVaddF32)                    \
@@ -104,7 +105,6 @@ namespace compiler {
   V(ArmPush)                       \
   V(ArmPoke)
 
-
 // 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