Assert that OBJ_TMPFS flag on the vm object for the tmpfs node is
cleared when the tmpfs node is going away.

Tested by:	bdrewery, pho
Remove the capitalization in the assertion message.  Print the address
of the object to get useful information from optimizated kernels dump.
After the object lock was dropped, the object' reference count could
change.  Retest the ref_count and return from the function to not
execute the further code which assumes that ref_count == 1 if it is
not.  Also, do not leak vnode lock if other thread cleared OBJ_TMPFS
flag meantime.

Reported by:	bdrewery
Tested by:	bdrewery, pho
Sponsored by:	The FreeBSD Foundation