Make SchedulerMutex non-recursive

While thinking about the "Unlock scheduler in deinit for
ProcessEventsToIdle" patch, I came to the conclusion, that this
mutex should actually be non-recursive. I had a look at the code
and did run "make check" for my symbol build on Linux, but for
the rest I'm reying on the LO CI.

Maybe this can be converted to a std::mutex later. I've updated
the vcl/README.scheduler and added a TODO.

Change-Id: Ib9cb086af74b51e48f99ebfa1201d14db12b140e
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/107254
Tested-by: Jenkins
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>

0 files changed, 0 insertions, 0 deletions