[autofill] Update AutofillSmallFormSupport fieldtrial

This CL updates the AutofillSmallFormSupport fieldtrial config to match
the feature permutation planned to go the beta/stable for password
manager small form support.

Bug: 824834
Change-Id: Ic58ac339f5dc8004c0e6a3b7f7eedc6207db2736
Reviewed-on: https://chromium-review.googlesource.com/1169975Reviewed-by: Robert Kaplow (slow) <rkaplow@chromium.org>
Commit-Queue: Roger McFarlane <rogerm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#582156}

testing/variations/fieldtrial_testing_config.json

@@ -545,10 +545,12 @@
             "experiments": [
                 {
                     "name": "Enabled",
-                    "disable_features": [
+                    "enable_features": [
                         "AutofillEnforceMinRequiredFieldsForHeuristics",
+                        "AutofillEnforceMinRequiredFieldsForUpload"
+                    ],
+                    "disable_features": [
                         "AutofillEnforceMinRequiredFieldsForQuery",
-                        "AutofillEnforceMinRequiredFieldsForUpload",
                         "AutofillRestrictUnownedFieldsToFormlessCheckout"
                     ]
                 }