Add field trial for bank name experiment on all platforms.

Bug: 734265
Change-Id: Id9690f81213561c1808532c85b41e61ecda81adc
Reviewed-on: https://chromium-review.googlesource.com/794412Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Mathieu Perreault <mathp@chromium.org>
Commit-Queue: Shanfeng Zhang <szhangcs@google.com>
Cr-Commit-Position: refs/heads/master@{#519868}

testing/variations/fieldtrial_testing_config.json

@@ -399,10 +399,15 @@
             ]
         }
     ],
-    "AutofillCreditCardDropdownVariations": [
+    "AutofillCreditCardBankNameDisplay": [
         {
             "platforms": [
-                "android"
+                "android",
+                "chromeos",
+                "ios",
+                "linux",
+                "mac",
+                "win"
             ],
             "experiments": [
                 {