[Patch] Move code for error "Area style way is not closed" to UnclosedWays

[GerdP]

Don't know why this message is produced by MultipolygonTest instead of UnclosedWays.

The message is produced for unclosed ways with e.g. just one tag highway=services.

The attached patch moves the corresponding code from MultipolygonTest to UnclosedWays
and the message to the error group "Unclosed way" with new error code 1131 (old was 1609)

@Klumbumbus:
With r15094 we get two messages for such a way with highway=services. Is that intended?

[Klumbumbus]

For the example tag combination from #17623 (highway=trunk + junction=yes) on a unclosed way the "Area style way is not closed" warning doesn't show up, thats why I wasn't aware of that test while creating r15094.

The "Area style way is not closed" test and the second rule in r15094 have little different goals. (The first "assumes" the area is not closed, i.e. error in geometry while the second "assumes" that there is an error in the tags.) Not sure if and how they could be merged.

[GerdP]

Ah, probably the list in the new rule needs $ and ^ so that service doesn't match services?

[Klumbumbus]

Ah, now I get it. So yes and no. The missing $ and ^ are intended to match all the ..._link highways. However services should not match as this is used on areas. I'll fix the rule.

[Klumbumbus]

In 15131/josm:

see #17623 , see #17765 - fix validator warning, don't treat highway=services as linear object

[Klumbumbus]

(I wanted to add asserts but they didn't work due to the :AreaStyle pseudo class)

[GerdP]

In 15132/josm:

fix #17765: Move code for error "Area style way is not closed" to UnclosedWays
This simplifies the code. Method UnclosedWays.getCheckedKeys() is no longer needed
by any code in core or the plugins directory, but I did not dare to remove it.

[GerdP]

In 15133/josm:

see #17765: Further simplify code

[Don-vip]

MultipolygonTestTest.testTicket10469 is failing.

[GerdP]

Oops, I only looked at the file multipolygon.osm...
I'll add a new test for UnclosedWays.

[GerdP]

In 15134/josm:

see #17765: fix / add unit tests