PR14705: Modify SDT semaphores in stapdyn

PR14705: Modify SDT semaphores in stapdyn

For SDT probes which are guarded by a semaphore, stapdyn needs to update
the value to show when the probes are active.

* stapdyn/mutatee.h (mutatee::semaphores): New vector of variables in
  this mutatee which represent active semaphores.
* stapdyn/mutatee.cxx (mutatee::update_semaphores): New, used to
  increment or decrement the value of semaphores in this mutatee.
  (mutatee::instrument_dynprobe_target): When a probe has a semaphore,
  create a variable representation of it.
  (mutatee::instrument_object_dynprobes): Increment semaphores in bulk.
  (mutatee::copy_forked_instrumentation): Copy semaphore variables too.
  (mutatee::remove_instrumentation): Decrement semaphores in bulk.
* tapsets.cxx (sdt_query::handle_query_module): Calculate the difference
  in load addresses between .text and .data as semaphore_load_offset.
  (sdt_query::record_semaphore): Subtract the semaphore_load_offset for
  dyninst to get a file-based offset of the semaphore.