Double KENTRY_DATA_SIZE

* vm/vm_map.h (KENTRY_DATA_SIZE): Bump from 32 pages to 64 pages.
Add function to dump a raw summary of the slab allocator state

The purpose of this function is to allow kernel code to display the state
of the slab caches in situations where the host_slab_info RPC wouldn't be
available, e.g. before a panic.

* kern/slab.c (slab_info): New function.
* kern/slab.h: Add declaration for slab_info.
Fix slab cache list locking

This problem was overlooked because of simple locks being no-ops.

* kern/slab.c (slab_collect): Fix lock name to kmem_cache_list_lock.
(host_slab_info): Likewise.
Add statistics for task_events_info

* ipc/ipc_mqueue.c (ipc_mqueue_send, ipc_mqueue_receive): Increment
counters for message sent and received.
* kern/ipc_kobject.c (ipc_kobject_server): Increment sent and received
counters for the kernel task.
* kern/task.c (task_create): Zero statistics.
* kern/task.c (task_info): Add task_events_info call.
* kern/task.h: Add statistics.
* vm/vm_fault.c (vm_fault_page): Increment zero_fills, pageins,
reactivations and cow_faults counters.
* vm/vm_fault.c (vm_fault_wire_fast): Increment faults counters.
* vm/vm_pageout.c (vm_pageout_scan): Increment reactivations counter.
Fix task stats incrementations

* vm/vm_fault.c (vm_fault_page): Properly increment
current_task()->zero_fills and cow_faults.
Merge branch 'master' of git.savannah.gnu.org:/srv/git/hurd/gnumach