TStreamerElement cached strings changed to thread_local
TStreamerElement cached strings changed to thread_local

Full name and include name were statics which were set the first time
called. This was not thread safe. These were changed to thread_local.
Alternatively, this could be change to use std::call_once.

Dr15Jones/root,Dr15Jones/root,Dr15Jones/root,Dr15Jones/root,Dr15Jones/root,Dr15Jones/root,Dr15Jones/root