Revert of Fix clobbered register when setting this_function variable.

src/ia32/full-codegen-ia32.cc

Index: src/ia32/full-codegen-ia32.cc
diff --git a/src/ia32/full-codegen-ia32.cc b/src/ia32/full-codegen-ia32.cc
index 6cbe73fd70178f2831e9ec47fc279f4fab1d1f40..202740b385cc93bef3ba8e9a966d8d6a2708f004 100644
--- a/src/ia32/full-codegen-ia32.cc
+++ b/src/ia32/full-codegen-ia32.cc
@@ -239,10 +239,6 @@
   Variable* this_function_var = scope()->this_function_var();
   if (this_function_var != nullptr) {
     Comment cmnt(masm_, "[ This function");
-    if (!function_in_register) {
-      __ mov(edi, Operand(ebp, JavaScriptFrameConstants::kFunctionOffset));
-      function_in_register = true;
-    }
     SetVar(this_function_var, edi, ebx, edx);
   }