Add one more x_display_ field to fields-to-ignore.txt

Bug: 1069567
Change-Id: I5b039c91a070e1dd327b9314f44e04fcdaff088a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2241360
Commit-Queue: Bartek Nowierski <bartekn@chromium.org>
Commit-Queue: Daniel Cheng <dcheng@chromium.org>
Auto-Submit: Bartek Nowierski <bartekn@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#777315}

tools/clang/rewrite_raw_ptr_fields/fields-to-ignore.txt

@@ -81,6 +81,7 @@ remoting::ClipboardX11::display_
 remoting::XServerClipboard::display_
 Simulator::display_
 ui::ClipboardX11::X11Details::x_display_
+ui::SelectionRequestorTest::x_display_
 ui::X11EventSource::display_
 ui::X11MenuRegistrar::xdisplay_
 ui::X11WorkspaceHandler::xdisplay_