Revert of Fix clobbered register when setting this_function variable.

src/x87/full-codegen-x87.cc

Index: src/x87/full-codegen-x87.cc
diff --git a/src/x87/full-codegen-x87.cc b/src/x87/full-codegen-x87.cc
index f934d37385ae148462fe3f59d3ce3681a7fd4d13..e2abd9d311181c39cf4e8b17f26aea0c4138bf1d 100644
--- a/src/x87/full-codegen-x87.cc
+++ b/src/x87/full-codegen-x87.cc
@@ -236,10 +236,6 @@
   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);
   }