Revert "Update test filters to androidx."

This reverts commit b5af1d8d.

Reason for revert: instrumentation registry isn't working on other builders. https://ci.chromium.org/p/chromium/builders/ci/Mojo%20Android/19484

Original change's description:
> Update test filters to androidx.
> 
> Bug: 1005891
> Change-Id: If459301ac9a4b419cdbd487222754d19767f24ef
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1814691
> Reviewed-by: Yuwei Huang <yuweih@chromium.org>
> Commit-Queue: benjamin joyce <bjoyce@google.com>
> Cr-Commit-Position: refs/heads/master@{#698246}

TBR=jamiewalch@chromium.org,lambroslambrou@chromium.org,garykac@chromium.org,joedow@chromium.org,yuweih@chromium.org,bjoyce@google.com

Change-Id: Ib8b6bdb9e1b98973ab1e7f2cc2f5b34336097cbb
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1005891
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1816361Reviewed-by: Yuwei Huang <yuweih@chromium.org>
Commit-Queue: benjamin joyce <bjoyce@google.com>
Cr-Commit-Position: refs/heads/master@{#698573}

remoting/android/BUILD.gn

@@ -98,8 +98,7 @@ instrumentation_test_apk("remoting_test_apk") {
     ":remoting_android_client_java",
     "//base:base_java",
     "//base:base_java_test_support",
-    "//third_party/android_deps:androidx_test_monitor_java",
-    "//third_party/android_deps:androidx_test_runner_java",
+    "//third_party/android_support_test_runner:runner_java",
     "//third_party/junit:junit",
   ]
 }

remoting/android/javatests/src/org/chromium/chromoting/EventTest.java

@@ -6,9 +6,8 @@ package org.chromium.chromoting;
 
 import android.os.Handler;
 import android.os.Looper;
-
-import androidx.test.filters.MediumTest;
-import androidx.test.filters.SmallTest;
+import android.support.test.filters.MediumTest;
+import android.support.test.filters.SmallTest;
 
 import org.junit.Assert;
 import org.junit.Test;

remoting/android/javatests/src/org/chromium/chromoting/SwipePinchDetectorTest.java

@@ -6,13 +6,12 @@ package org.chromium.chromoting;
 
 import android.content.Context;
 import android.os.SystemClock;
+import android.support.test.InstrumentationRegistry;
+import android.support.test.filters.SmallTest;
 import android.view.InputDevice;
 import android.view.MotionEvent;
 import android.view.ViewConfiguration;
 
-import androidx.test.InstrumentationRegistry;
-import androidx.test.filters.SmallTest;
-
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;

remoting/android/javatests/src/org/chromium/chromoting/TapGestureDetectorTest.java

@@ -4,12 +4,11 @@
 
 package org.chromium.chromoting;
 
+import android.support.test.InstrumentationRegistry;
+import android.support.test.filters.SmallTest;
 import android.view.MotionEvent;
 import android.view.ViewConfiguration;
 
-import androidx.test.InstrumentationRegistry;
-import androidx.test.filters.SmallTest;
-
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;

remoting/android/javatests/src/org/chromium/chromoting/TouchInputStrategyTest.java

@@ -5,10 +5,9 @@
 package org.chromium.chromoting;
 
 import android.graphics.PointF;
+import android.support.test.filters.SmallTest;
 import android.view.MotionEvent;
 
-import androidx.test.filters.SmallTest;
-
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;