[autofill] Inject only the necessary JS requred for the test

Bug: 896719
Change-Id: I52ae96084f32210ef187a023fa6090f57928a654
Reviewed-on: https://chromium-review.googlesource.com/c/1330343Reviewed-by: Olivier Robin <olivierrobin@chromium.org>
Commit-Queue: Roger McFarlane <rogerm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606974}

components/autofill/ios/form_util/fill_js_unittest.mm

@@ -21,8 +21,7 @@ namespace {
 class FillJsTest : public web::WebJsTest<web::WebTestWithWebState> {
  public:
   FillJsTest()
-      : web::WebJsTest<web::WebTestWithWebState>(
-            @[ @"chrome_bundle_all_frames" ]) {}
+      : web::WebJsTest<web::WebTestWithWebState>(@[ @"form_util_js" ]) {}
 };
 
 }  // namespace