Re-enable testTouchScrollCanBeAlteredByUi

- There was no flake in the test history on FYI bot recently,
- There is no stack trace available from the bot.
- Not locally reproducible.

Re-enable this test to get the stack traces and see if flakiness can
still be reproduced.

        50 times on emulator out of 50 trials

Tested: passed AndroidScrollIntegrationTest#testTouchScrollCanBeAlteredByUi
Bug: 813837
Change-Id: Ibb240d0720a223c20f8d815c0c0fa6d4246a7e8d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2411147
Commit-Queue: Changwan Ryu <changwan@chromium.org>
Reviewed-by: Nate Fischer <ntfschr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#806768}

android_webview/javatests/src/org/chromium/android_webview/test/AndroidScrollIntegrationTest.java

@@ -449,13 +449,8 @@ public void testJsScrollCanBeAlteredByUi() throws Throwable {
     }
 
     @Test
-    /**
-     * @SmallTest
-     * @Feature({"AndroidWebView"})
-     * BUG=813837
-     */
-    // Originally flaked only in multi-process mode (http://crbug.com/616505)
-    @DisabledTest
+    @SmallTest
+    @Feature({"AndroidWebView"})
     public void testTouchScrollCanBeAlteredByUi() throws Throwable {
         final TestAwContentsClient contentsClient = new TestAwContentsClient();
         final ScrollTestContainerView testContainerView =