[android] Disable 3 failing accessibility-related content browsertests.

DumpAccessibilityTreeTest.AccessibilityDialog
DumpAccessibilityTreeTest.AccessibilityModalDialogClosed
DumpAccessibilityTreeTest.AccessibilityModalDialogInIframeOpened

BUG=297230
TBR=dmazzoni@chromium.org
NOTRY=True

Review URL: https://codereview.chromium.org/68983006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235740 0039d316-1c4b-4281-b951-d872f2087c98

build/android/pylib/gtest/filter/content_browsertests_disabled

@@ -38,6 +38,9 @@ DomSerializerTests.*
 DumpAccessibilityTreeTest.AccessibilityCanvas
 RendererAccessibilityTest.DetachAccessibilityObject
 RendererAccessibilityTest.EditableTextModeFocusEvents
+DumpAccessibilityTreeTest.AccessibilityDialog
+DumpAccessibilityTreeTest.AccessibilityModalDialogClosed
+DumpAccessibilityTreeTest.AccessibilityModalDialogInIframeOpened
 
 # http://crbug.com/187500
 RenderViewImplTest.*