platform roles membership should be moved to newly created multipolygon (in route=tram/subway/light_rail/train/trolleybus/bus relations)

[mkoniecz]

What steps will reproduce the problem?

1. download ​https://www.openstreetmap.org/way/655027220 ( Relation Tram 2: Cmentarz Rakowicki => Salwator (176853) (as platform) )
2. select ​https://www.openstreetmap.org/way/655027220
3. use ctrl-b (create multipolygon)

What is the expected result?

platform membership role is moved to newly created multipolygon rather than stay on soon to be splitted way

What happens instead?

platform membership role is not moved to newly created multipolygon and stays on soon to be splitted way

bus OSM wiki page claims that also platform_exit_only and platform_entry_only roles may exist - these also should be moved to a new multipolygon.

Please provide any additional information below. Attach a screenshot if possible.

​https://wiki.openstreetmap.org/wiki/Tag:route%3Dtram
​https://wiki.openstreetmap.org/wiki/Tag:route%3Dsubway
​https://wiki.openstreetmap.org/wiki/Tag:route%3Dlight_rail
​https://wiki.openstreetmap.org/wiki/Tag:route%3Dtrain
​http://wiki.openstreetmap.org:80/wiki/Tag:route=trolleybus
​https://wiki.openstreetmap.org/wiki/Tag:route%3Dbus

URL:https://josm.openstreetmap.de/svn/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2018-12-17 22:42:01 +0100 (Mon, 17 Dec 2018)
Build-Date:2018-12-18 02:32:19
Revision:14575
Relative:URL: ^/trunk

Identification: JOSM/1.5 (14575 en) Linux Ubuntu 16.04.5 LTS
Memory Usage: 678 MB / 869 MB (158 MB allocated, but free)
Java version: 1.8.0_191-b12, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
Screen: :0.0 1920x1080
Maximum Screen Size: 1920x1080
Dataset consistency test: No problems found

Plugins:
+ OpeningHoursEditor (34535)
+ buildings_tools (34724)
+ continuosDownload (82)
+ imagery_offset_db (34641)
+ measurement (34529)
+ reverter (34552)
+ todo (30306)

Last errors/warnings:
- E: java.net.SocketTimeoutException: Read timed out
- W: org.openstreetmap.josm.io.OsmTransferException: Could not connect to the OSM server. Please check your internet connection.. Cause: java.net.SocketTimeoutException: Read timed out
- W: java.net.SocketTimeoutException: Read timed out
- W: Already here java.net.SocketTimeoutException: Read timed out
- E: java.net.SocketTimeoutException: Read timed out
- W: org.openstreetmap.josm.io.OsmTransferException: Could not connect to the OSM server. Please check your internet connection.. Cause: java.net.SocketTimeoutException: Read timed out
- W: java.net.SocketTimeoutException: Read timed out
- W: Already here java.net.SocketTimeoutException: Read timed out
- E: java.net.SocketTimeoutException: Read timed out
- W: org.openstreetmap.josm.io.OsmTransferException: Could not connect to the OSM server. Please check your internet connection.. Cause: java.net.SocketTimeoutException: Read timed out