[ia32,root] Remove porting helper function

TBR=sigurds@chromium.org

Bug: v8:6666
Change-Id: I85dbc33a4baf5fb3775a6f557fc146437e17ab80
Reviewed-on: https://chromium-review.googlesource.com/c/1276430Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56585}

src/ia32/macro-assembler-ia32.h

@@ -246,13 +246,6 @@ class V8_EXPORT_PRIVATE TurboAssembler : public TurboAssemblerBase {
 
   void LoadRoot(Register destination, RootIndex index) override;
 
-  void MoveForRootRegisterRefactoring(Register dst, Register src) {
-    // TODO(v8:6666): When rewriting ia32 ASM builtins to not clobber the
-    // kRootRegister ebx, most call sites of this wrapper function can probably
-    // be removed.
-    Move(dst, src);
-  }
-
   // Indirect root-relative loads.
   void LoadFromConstantsTable(Register destination,
                               int constant_index) override;