KNL-1280 fix for NPE in caching race condition

git-svn-id: https://source.sakaiproject.org/svn/kernel@310784 66ffb92e-73f9-0310-93c1-f5514f145a0a
KNL-1279 fix for ConcurrentModificationException in BaseSitePage with memory.use.legacy=false

git-svn-id: https://source.sakaiproject.org/svn/kernel@310788 66ffb92e-73f9-0310-93c1-f5514f145a0a
SAK-26632 - Remove es_ES files

Also added some missing fallback.

git-svn-id: https://source.sakaiproject.org/svn/kernel@310804 66ffb92e-73f9-0310-93c1-f5514f145a0a
SAK-26632 - Remove es_ES files. Merge into 10.x

Also added some missing fallback.

git-svn-id: https://source.sakaiproject.org/svn/kernel@310805 66ffb92e-73f9-0310-93c1-f5514f145a0a