preserve original exception thrown for machine arch ctors

to not "eat" the original exception, we can just set it in the IllegalArgumentException's cause, see https://docs.oracle.com/javase/7/docs/api/java/lang/Throwable.html#getCause()

closes: #2146

src/main/scala/li/cil/oc/server/machine/Machine.scala

@@ -1027,7 +1027,7 @@ object Machine extends MachineAPI {
         architecture.getConstructor(classOf[machine.Machine])
       }
       catch {
-        case t: Throwable => throw new IllegalArgumentException("Architecture does not have required constructor.")
+        case t: Throwable => throw new IllegalArgumentException("Architecture does not have required constructor.", t)
       }
       checked += architecture
     }