Temporarily Disable Extra Mac Nodes for some accessibility dump tree tests

While trying to stabilize some flaky tests, the following tests began
crashing due to Extra Mac Nodes, likely due to the timing of when
Dump(...) is called.

Disabling Extra Mac Nodes and updating the expected files for the
affected tests.

Bug: 1172508, 1152126
Change-Id: I576335b4016e1de9bcc213e4d866a8e046256ecb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2660075


Commit-Queue: Adam Ettenberger <Adam.Ettenberger@microsoft.com>
Reviewed-by: Aaron Leventhal <aleventhal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#848815}