Windows: LockOrderValidation memory usage optimization

Windows: LockOrderValidation memory usage optimization

Instead of using malloc() and free() to allocation lock reference
structures, cache allocated objects in a free list.  This reduces
memory fragmentation.

Reviewed-on: http://gerrit.openafs.org/5159
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>
(cherry picked from commit 17e50a4b98de057a699681261ba126a5ac12a0cc)

Change-Id: Ifc8d7b6a92e32557575e24cec7513f890439ce67
Reviewed-on: http://gerrit.openafs.org/5209
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>