(PR14637 partial fix) Improve stapdyn locking.

(PR14637 partial fix) Improve stapdyn locking.

* runtime/dyninst/runtime.h: Remove the 'stapdyn_big_dumb_lock' and make
  preempt_disable() and preempt_enable_no_resched() do nothing for
  dyninst.
* runtime/dyninst/tls_data.c: Change the mutex in tls_data_container_t to
  a rwlock.
  (_stp_tls_free_per_thread_ptr): Write lock the container before remove
  the object from the list (and reduce the amount of time the container is
  locked).
  (_stp_tls_get_per_thread_ptr): Write lock the container before adding
  the object from the list (and reduce the amount of time the container is
  locked).
* runtime/map.c (_stp_pmap_agg): Be sure to unlock the map in error
  conditions.
* runtime/pmap-gen.c (KEYSYM(_stp_pmap_get)): Be sure to unlock the
  container in an error condition.