Remove CHECK on AXPlatformNodeAuraLinux::OnNameChanged()

This is a follow-up cl of https://crrev.com/c/2103997.
It should not have CHECK with the return value from
GetOrCreateAtkObject() since it could return nullptr.

Bug: 1061429
Change-Id: I5258ddfa5cb61a350c20886644804daad9a6dd57
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2114601
Commit-Queue: Julie Kim <jkim@igalia.com>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#752649}

ui/accessibility/platform/ax_platform_node_auralinux.cc

@@ -3755,7 +3755,6 @@ void AXPlatformNodeAuraLinux::OnValueChanged() {
 void AXPlatformNodeAuraLinux::OnNameChanged() {
   AtkObject* atk_object = GetOrCreateAtkObject();
   if (!atk_object) {
-    CHECK(false);
     return;
   }
   std::string previous_accessible_name = accessible_name_;