Disable BookmarksCommandManagerTest.All

The test was flaky before Nov 2019 and disabled in crrev.com/c/1898295.
However crrev.com/c/1917946 re-enabled it perhaps by accident. It's
still flaky:
https://analysis.chromium.org/p/chromium/flake-portal/flakes/occurrences?key=ag9zfmZpbmRpdC1mb3ItbWVyQQsSBUZsYWtlIjZjaHJvbWl1bUBicm93c2VyX3Rlc3RzQEJvb2ttYXJrc0NvbW1hbmRNYW5hZ2VyVGVzdC5BbGwM

TBR=hcarmona@chromium.org

Bug: 1010381, 1040698
Change-Id: I96d9a13efdce7a1c3dd6127efb8608d29a3c6335
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2026025Reviewed-by: Yi Gu <yigu@chromium.org>
Commit-Queue: Yi Gu <yigu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#736168}

chrome/test/data/webui/bookmarks/bookmarks_browsertest.js

@@ -67,7 +67,7 @@ var BookmarksCommandManagerTest = class extends BookmarksBrowserTest {
 };
 
 // https://crbug.com/1010381: Flaky.
-TEST_F('BookmarksCommandManagerTest', 'All', function() {
+TEST_F('BookmarksCommandManagerTest', 'DISABLED_All', function() {
   mocha.run();
 });