Validation of big multipolygon takes too much time (more than 1 hour)

[Vort_]

What steps will reproduce the problem?

1. Load lake_broken.osm
2. Start validation

What is the expected result?

Validation is finished.

What happens instead?

Validator hangs.

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

URL:http://josm.openstreetmap.de/svn/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2015-11-24 00:04:12 +0100 (Tue, 24 Nov 2015)
Build-Date:2015-11-23 23:14:21
Revision:9060
Relative:URL: ^/trunk

Identification: JOSM/1.5 (9060 ru) Windows 7 64-Bit
Memory Usage: 125 MB / 1801 MB (46 MB allocated, but free)
Java version: 1.8.0_05, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
VM arguments: [-Djava.security.policy=file:D:\Java_x64\jre8\lib\security\javaws.policy, -DtrustProxy=true, -Djnlpx.home=<java.home>\bin, -Djnlpx.origFilenameArg=C:\Users\Vort\AppData\LocalLow\Sun\Java\Deployment\cache\6.0\56\1ee8cfb8-564901be, -Djnlpx.remove=false, -Dsun.awt.warmup=true, -Djava.util.Arrays.useLegacyMergeSort=true, -Djnlpx.splashport=47732, -Djnlp.application.href=https://josm.openstreetmap.de/download/josm.jnlp, -Djnlpx.jvm=<java.home>\bin\javaw.exe, -Djnlpx.vmargs=-Djava.util.Arrays.useLegacyMergeSort=true -d64 -Djnlp.application.href=https://josm.openstreetmap.de/download/josm.jnlp]

Plugins:
- ext_tools (31772)
- reverter (31772)
- undelete (31772)

[Vort_]

Test file

[GerdP]

I've tested this with r10962 with jre1.8.0_102 on a 64 Bit Windows 10 system with 8GB, core i5-3550 cpu

The validation took ~262 seconds and found 103 problems. I think the major performance problem was solved with r10684.
(I've also tested it with all my patches, result : ~155 seconds, 143 problems)

[Vort_]

r10786: finished in ~4 minutes on my PC. Thanks!