Fix 0xC bugcheck in multiple object wait.
Fix 0xC bugcheck in multiple object wait.

Signed-off-by: Paul Durrant <dba6cd059c0054f8a3c62ba902cd9d7238853ee4@citrix.com>

QubesOS/qubes-vmm-xen-win-pvdrivers-xenbus,omeg/xenbus,MarkKMueller/xenbus,MarkKMueller/xenbus,xenserver/win-xenbus,xenserver/win-xenbus,xenserver/win-xenbus,rneilturner/xenbus,omeg/xenbus,omeg/xenbus,xenserver/win-xenbus,MarkKMueller/xenbus,QubesOS/qubes-vmm-xen-win-pvdrivers-xenbus,rneilturner/xenbus,QubesOS/qubes-vmm-xen-win-pvdrivers-xenbus,rneilturner/xenbus