Revert "Changing string length field type from int to SMI."

src/x64/macro-assembler-x64.h

Index: src/x64/macro-assembler-x64.h
diff --git a/src/x64/macro-assembler-x64.h b/src/x64/macro-assembler-x64.h
index 2a13e0bdd6f5697380c1aefe28db904f5e4f723d..10110d35eebb3765357ef99596c813e15bce7295 100644
--- a/src/x64/macro-assembler-x64.h
+++ b/src/x64/macro-assembler-x64.h
@@ -197,7 +197,6 @@ class MacroAssembler: public Assembler {
   // Simple comparison of smis.
   void SmiCompare(Register dst, Register src);
   void SmiCompare(Register dst, Smi* src);
-  void SmiCompare(Register dst, const Operand& src);
   void SmiCompare(const Operand& dst, Register src);
   void SmiCompare(const Operand& dst, Smi* src);
   // Sets sign and zero flags depending on value of smi in register.
@@ -288,8 +287,7 @@ class MacroAssembler: public Assembler {
                       Label* on_not_smi_result);
 
   // Subtract an integer constant from a tagged smi, giving a tagged smi as
-  // result. No testing on the result is done. Sets the N and Z flags
-  // based on the value of the resulting integer.
+  // result. No testing on the result is done.
   void SmiSubConstant(Register dst, Register src, Smi* constant);
 
   // Subtract an integer constant from a tagged smi, giving a tagged smi as
@@ -321,11 +319,6 @@ class MacroAssembler: public Assembler {
               Register src2,
               Label* on_not_smi_result);
 
-  void SmiSub(Register dst,
-              Register src1,
-              Operand const& src2,
-              Label* on_not_smi_result);
-
   // Multiplies smi values and return the result as a smi,
   // if possible.
   // If dst is src1, then src1 will be destroyed, even if