Frame stacking fix and unit test addition. (#56287)

* Reverts #56205

* Allow things without density to bypass checks

* The rest of the owl

* The rest of the owl

* Doc and tweak

* More feex

* RCD machine frame unit test

* I suck

* AAAAA

* Bad at unit tests

* Revert unit tests (for including in another PR)

* Fix windoor_assembly return logic

* Comment /mob/living/proc/PushAM logic

* Windoor assembley logic tweak

* Fix frame stacking

* Unit test

* Better wording from macros?

code/modules/reagents/chemistry/machinery/reagentgrinder.dm

@@ -12,7 +12,6 @@
 	circuit = /obj/item/circuitboard/machine/reagentgrinder
 	pass_flags = PASSTABLE
 	resistance_flags = ACID_PROOF
-	anchorables = list(/obj/structure/table)
 	var/operating = FALSE
 	var/obj/item/reagent_containers/beaker = null
 	var/limit = 10