[csa] Respect --force-slow-path in array iterator's next().

This might have enabled our fuzzing to find the recent bug.

R=bmeurer@chromium.org

Bug: v8:8449
Change-Id: Iaa485061e132a9d20b995478dd9a642e2224f435
Reviewed-on: https://chromium-review.googlesource.com/c/1337588Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57541}

src/builtins/builtins-array-gen.cc

@@ -3459,6 +3459,7 @@ TF_BUILTIN(ArrayIteratorPrototypeNext, CodeStubAssembler) {
     Label if_hole(this, Label::kDeferred);
     TNode<Int32T> elements_kind = LoadMapElementsKind(array_map);
     TNode<FixedArrayBase> elements = LoadElements(CAST(array));
+    GotoIfForceSlowPath(&if_generic);
     var_value.Bind(LoadFixedArrayBaseElementAsTagged(
         elements, Signed(ChangeUint32ToWord(index32)), elements_kind,
         &if_generic, &if_hole));