Change fieldtrial testing config for bank name experiment

Bug: 734265
Change-Id: Ia341474fe1134b3105ab97067fbbbc6e61a93a58
Reviewed-on: https://chromium-review.googlesource.com/562096Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Commit-Queue: Shanfeng Zhang <szhangcs@google.com>
Cr-Commit-Position: refs/heads/master@{#484975}

testing/variations/fieldtrial_testing_config.json

@@ -147,13 +147,9 @@
             ],
             "experiments": [
                 {
-                    "name": "LastUsedDate_IncreaseDropdownItemHeight_Experiment",
-                    "params": {
-                        "dropdown_item_height": "56"
-                    },
+                    "name": "BankName_Experiment",
                     "enable_features": [
-                        "AutofillCreditCardLastUsedDateDisplay",
-                        "AutofillCreditCardPopupLayout"
+                        "AutofillCreditCardBankNameDisplay"
                     ]
                 }
             ]