[turbofan] Turn Math.clz32 into an inlinable builtin.

src/ia32/macro-assembler-ia32.h

Index: src/ia32/macro-assembler-ia32.h
diff --git a/src/ia32/macro-assembler-ia32.h b/src/ia32/macro-assembler-ia32.h
index 8c135f2b6021c9b71e5dbf3eea44138fedb7c7a3..8a8ee2a30e722b369cef852cdd2977f35e307e5c 100644
--- a/src/ia32/macro-assembler-ia32.h
+++ b/src/ia32/macro-assembler-ia32.h
@@ -820,6 +820,9 @@ class MacroAssembler: public Assembler {
   }
   void Pinsrd(XMMRegister dst, const Operand& src, int8_t imm8);
 
+  void Lzcnt(Register dst, Register src) { Lzcnt(dst, Operand(src)); }
+  void Lzcnt(Register dst, const Operand& src);
+
   // Emit call to the code we are currently generating.
   void CallSelf() {
     Handle<Code> self(reinterpret_cast<Code**>(CodeObject().location()));