posix: Delete POSIX_Keys_Freechain type

Use the POSIX configuration value directly.  Use right type early and
avoid casts.  Use proper unlimited objects API.  Check workspace
allocation.  Make functions static.
PR766: Delete __RTEMS_APPLICATION__

This define is no longer used.
PR766: Delete __RTEMS_INSIDE__
PR766: Delete __RTEMS_VIOLATE_KERNEL_VISIBILITY__
score: Rename _Scheduler_priority_Release_job()

Rename _Scheduler_priority_Release_job() into
_Scheduler_default_Release_job().
score: Rename _Scheduler_simple_Allocate(), etc.

Rename _Scheduler_simple_Allocate() in _Scheduler_default_Allocate().
Rename _Scheduler_simple_Free() in _Scheduler_default_Free().
score: Rename _Scheduler_simple_Update()

Rename _Scheduler_simple_Update() in _Scheduler_default_Update().
smptests/smpmigration01: Fix start sequence

Start the runner after the context is initialized.
sptests/spintrcritical19: PR2136: New test