Disable TestSetCaretSetsSequentialFocusNavigationStartingPoint on MSan

This test is flaky on MSan.

TBR=mrobinson@igalia.com

Bug: 981913
Change-Id: I8ece439d23b7302575166c90a3b681145e503e58
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1761168Reviewed-by: Marina Ciocea <marinaciocea@chromium.org>
Commit-Queue: Marina Ciocea <marinaciocea@chromium.org>
Cr-Commit-Position: refs/heads/master@{#688955}

content/browser/accessibility/accessibility_auralinux_browsertest.cc

@@ -17,8 +17,8 @@
 #include "content/test/content_browser_test_utils_internal.h"
 #include "ui/accessibility/platform/ax_platform_node_auralinux.h"
 
-// TODO(crbug.com/981913): This flakes on linux tsan.
-#if defined(THREAD_SANITIZER)
+// TODO(crbug.com/981913): This flakes on linux tsan and msan.
+#if defined(THREAD_SANITIZER) || defined(MEMORY_SANITIZER)
 #define MAYBE_TestSetCaretSetsSequentialFocusNavigationStartingPoint \
   DISABLED_TestSetCaretSetsSequentialFocusNavigationStartingPoint
 #else