[Patch] Improve performance of some validator tests

[GerdP]

What steps will reproduce the problem?

1. Run validator on a download of a small city
2. Wonder why "ConditionalKeys" takes so long

What is the expected result?

Quick test because only a few objects have conditional keys

What happens instead?

Test needs > 2 secs

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

The simple patch avoids some calculations for all the objects without any tags, like most nodes
and thus reduces run time.
Same for OpeningHours.

Build-Date:2018-11-25 14:21:25
Revision:14442
Is-Local-Build:true

Identification: JOSM/1.5 (14442 SVN en) Windows 10 64-Bit
OS Build number: Windows 10 Home 1803 (17134)
Memory Usage: 1261 MB / 3641 MB (429 MB allocated, but free)
Java version: 1.8.0_191-b12, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
Screen: \Display0 1920x1080
Maximum Screen Size: 1920x1080
VM arguments: [-agentlib:jdwp=transport=dt_socket,suspend=y,address=localhost:54060, -ea, -Dfile.encoding=UTF-8]
Dataset consistency test: No problems found

Plugins:
+ OpeningHoursEditor (34535)
+ apache-commons (34506)
+ buildings_tools (34724)
+ download_along (34503)
+ ejml (34389)
+ geotools (34513)
+ importvec (34520)
+ jaxb (34506)
+ jts (34524)
+ merge-overlap (34664)
+ o5m (34405)
+ opendata (34698)
+ pbf (34576)
+ poly (34546)
+ reverter (34552)
+ undelete (34568)
+ utilsplugin2 (34506)

Last errors/warnings:
- W: Test 'Tag checker' completed in 166 ms
- W: Test 'Turnrestrictions' completed in 26 ms
- W: Test 'Unclosed Ways' completed in 33 ms
- W: Test 'Unconnected highways' completed in 196 ms
- W: Test 'Unconnected natural lands and landuses' completed in 84 ms
- W: Test 'Unconnected power ways' completed in 32 ms
- W: Test 'Untagged and unconnected nodes' completed in 39 ms
- W: Test 'Untagged, empty and one node ways' completed in 38 ms
- W: Test 'Way connected to Area' completed in 36 ms
- W: Test 'Wrongly Ordered Ways' completed in 27 ms

[GerdP]

In 14455/josm:

fix #17028: improve performance of some validator tests

[GerdP]

Hm, this doesn't have the expected effect. Seems that the JIT confused me. When you execute the validator for the first time
the ConditionalKeys still takes long, further executions are faster.
I see something like 2.8 secs -> 1.2 secs -> 0.8 secs -> 0.5 secs -> 0.4 secs.
So, what we see here is probably JIT in action. Sorry for the noise.