Disable flaky All/DumpAccessibilityTreeTest.AccessibilityAriaHiddenSingleDescendant*

Disabling new DumpAccessibilityTreeTest tests that are flaky :
- AccessibilityAriaHiddenSingleDescendant
- AccessibilityAriaHiddenSingleDescendantDisplayNone
- AccessibilityAriaHiddenSingleDescendantVisibilityHidden

https://ci.chromium.org/ui/p/chromium/builders/ci/Linux%20ChromiumOS%20MSan%20Tests/22224/overview

Bug: 1169854, 1159660
Change-Id: I350e3bdb66026410623a64f0dc04c3f62ce2f4ab
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2645257Reviewed-by: Katie Dektar <katie@chromium.org>
Reviewed-by: Kurt Catti-Schmidt <kschmi@microsoft.com>
Commit-Queue: Adam Ettenberger <Adam.Ettenberger@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#846386}

content/browser/accessibility/dump_accessibility_tree_browsertest.cc

@@ -739,20 +739,24 @@ IN_PROC_BROWSER_TEST_P(DumpAccessibilityTreeTest,
   RunAriaTest(FILE_PATH_LITERAL("aria-hidden-descendants.html"));
 }
 
+// TODO(crbug.com/1169854): Flaky
 IN_PROC_BROWSER_TEST_P(DumpAccessibilityTreeTest,
-                       AccessibilityAriaHiddenSingleDescendant) {
+                       DISABLED_AccessibilityAriaHiddenSingleDescendant) {
   RunAriaTest(FILE_PATH_LITERAL("aria-hidden-single-descendant.html"));
 }
 
-IN_PROC_BROWSER_TEST_P(DumpAccessibilityTreeTest,
-                       AccessibilityAriaHiddenSingleDescendantDisplayNone) {
+// TODO(crbug.com/1169854): Flaky
+IN_PROC_BROWSER_TEST_P(
+    DumpAccessibilityTreeTest,
+    DISABLED_AccessibilityAriaHiddenSingleDescendantDisplayNone) {
   RunAriaTest(
       FILE_PATH_LITERAL("aria-hidden-single-descendant-display-none.html"));
 }
 
+// TODO(crbug.com/1169854): Flaky
 IN_PROC_BROWSER_TEST_P(
     DumpAccessibilityTreeTest,
-    AccessibilityAriaHiddenSingleDescendantVisibilityHidden) {
+    DISABLED_AccessibilityAriaHiddenSingleDescendantVisibilityHidden) {
   RunAriaTest(FILE_PATH_LITERAL(
       "aria-hidden-single-descendant-visibility-hidden.html"));
 }