ARM64: Add and use SmiTagAndPush.

src/arm64/macro-assembler-arm64.h

Index: src/arm64/macro-assembler-arm64.h
diff --git a/src/arm64/macro-assembler-arm64.h b/src/arm64/macro-assembler-arm64.h
index 320681b6afbedb35d70e7f57bf15f565173b2680..551c0ea232e958565e354a2089f3fdb49af2e311 100644
--- a/src/arm64/macro-assembler-arm64.h
+++ b/src/arm64/macro-assembler-arm64.h
@@ -869,6 +869,10 @@ class MacroAssembler : public Assembler {
                               Register src,
                               UntagMode mode = kNotSpeculativeUntag);
 
+  // Tag and push in one step.
+  inline void SmiTagAndPush(Register src);
+  inline void SmiTagAndPush(Register src1, Register src2);
+
   // Compute the absolute value of 'smi' and leave the result in 'smi'
   // register. If 'smi' is the most negative SMI, the absolute value cannot
   // be represented as a SMI and a jump to 'slow' is done.