Disable CrSettingsCrostiniPageTest.All on ChromeOS dbg

The test is failing and the offending CL cannot be trivially reverted.

TBR=rjwright@chromium.org

No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 838097
Change-Id: I1f32a74ab6693f0532c9edc2cbc0af554b2ae656
Reviewed-on: https://chromium-review.googlesource.com/1034684Reviewed-by: Christos Froussios <cfroussios@chromium.org>
Commit-Queue: Christos Froussios <cfroussios@chromium.org>
Cr-Commit-Position: refs/heads/master@{#554724}

chrome/test/data/webui/settings/cr_settings_browsertest.js

@@ -1776,7 +1776,13 @@ CrSettingsCrostiniPageTest.prototype = {
   ]),
 };
 
-TEST_F('CrSettingsCrostiniPageTest', 'All', function() {
+GEN('#if defined(OS_CHROMEOS) && !defined(NDEBUG)');
+GEN('#define MAYBE_CROSTINI_All DISABLED_All');
+GEN('#else');
+GEN('#define MAYBE_CROSTINI_All All');
+GEN('#endif');
+
+TEST_F('CrSettingsCrostiniPageTest', 'MAYBE_CROSTINI_All', function() {
   mocha.run();
 });