pack_job_id was being reported as pack_job_offset

Get rid of any race conditions and call anything that was in
_pre_task_privileged from the parent instead of the child.

NOTE: This should be safe as we don't execute the task until after
_exec_wait_child_wait_for_parent is signaled which happens after all this is
long over.

Bug 3865

Fix regression in commit e5c05549 that would put the stepd pid into the memory cgroup instead of the task's pid.

Beforehand this would put the result of getpid() into the cgroup.  Before
e5c05549 this was done in the child of the fork which would get you
the task's pid, but moving it to run in the parent broke this logic.

What this patch does is adds pid to the input parameters of
task_g_pre_launch_priv making it so we could use the correct pid.

Regression in commit afeca4e2. Bug 4026.

Bug 3953

Pretty much fix the entire purpose of this max_agent_queue.

Bug 3159

Bug 3956

Bug 3967

step wasn't always gathered correctly.

Bug 3531

This removes several define statements with different names in
  various functions

Fix for possible slurmctld abort with use of salloc/sbatch/srun
    --gres-flags=enforce-binding option.
bug 4008

Update from commit b40bd8d3

Clarify --immediate option.

By removing the real locks we can get into a race condition where the prolog
starts and finishes before we get here and then we end up waiting forever.

Making the mutex a static seemed to help in many cases, but didn't
completely close the window.  Changing slurm_cond_wait to
slurm_cond_timedwait fixed the scenario where we would hit the window, but
not degrade performance the original commit provides.

There were also spots where if the job or step didn't exist it wouldn't
signal the conditional also providing a spot this could get stuck not
starting the job.

Fix regression from commit 52ce3ff0

Bug 3977

Fix for debugger setup bug introduced in commit
f1110568

Avoid interleaving labels and output from various components of
   a pack job

This allocates an array to the proper size (based upon all tasks
  to be launched). Work still needed to populate the data structure
  properly for all tasks.

No change in logic

The debugger symbol in srun is not being properly handled today.
  This change does the malloc once, even for a pack-job, makes
  the array over-sized, and range checks before writes. Suitable
  for making srun progress without memory errors (writing off end
  of allocated memory in an array).

Code provided by Ole Nielsen <Ole.H.Nielsen@fysik.dtu.dk>

Bug 3985