Reland "Autofill: Add fieldtrail testing for AndroidAutofillQueryServerFieldTypes"

This reverts commit bdb8bac7.

Reason for revert: Disabled the tests on x86 emulates, all tests should pass now.

Original change's description:
> Revert "Autofill: Add fieldtrail testing for AndroidAutofillQueryServerFieldTypes"
>
> This reverts commit 7452904e.
>
> Reason for revert: AwAutofillTest failures, see https://ci.chromium.org/ui/p/chromium/builders/ci/android-pie-x86-rel/3610/overview
>
> Original change's description:
> > Autofill: Add fieldtrail testing for AndroidAutofillQueryServerFieldTypes
> >
> > Bug: 1151542
> > Change-Id: I25545f36d588ca926ce1de9514ae919f3f441a64
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2628040
> > Commit-Queue: Weilun Shi <sweilun@chromium.org>
> > Reviewed-by: Weilun Shi <sweilun@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#843427}
>
> TBR=michaelbai@chromium.org,sweilun@chromium.org,chromium-scoped@luci-project-accounts.iam.gserviceaccount.com
>
> Change-Id: Id31bb7d9a0b420315d729b802c6634e5e9c59e71
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: 1151542
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2629971
> Reviewed-by: Sky Malice <skym@chromium.org>
> Commit-Queue: Sky Malice <skym@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#843702}

TBR=michaelbai@chromium.org,skym@chromium.org,sweilun@chromium.org,chromium-scoped@luci-project-accounts.iam.gserviceaccount.com

# Not skipping CQ checks because this is a reland.

Bug: 1151542
Change-Id: I9b2d003be6aa41643ad6dd209f4e63a5be2158e4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2631200Reviewed-by: Michael Bai <michaelbai@chromium.org>
Reviewed-by: Sky Malice <skym@chromium.org>
Commit-Queue: Michael Bai <michaelbai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#843934}

testing/variations/fieldtrial_testing_config.json

@@ -112,6 +112,22 @@
             ]
         }
     ],
+    "AndroidAutofillQueryServerFieldTypes": [
+        {
+            "platforms": [
+                "android_weblayer",
+                "android_webview"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "AndroidAutofillQueryServerFieldTypes"
+                    ]
+                }
+            ]
+        }
+    ],
     "AndroidDarkSearch": [
         {
             "platforms": [