Mapillary test failures with openjdk11

[Don-vip]

See jenkins/job/JOSM-Plugins/jdk=JDK11/lastCompletedBuild/testReport/

36 test failures, all from Mapillary plugin, but only with Java 11.

Worked fine before these changes:

    TEST: Junit4 -> JUnit 5 migration

    Signed-off-by: Taylor Smock <tsmock@fb.com> (détails)
    by taylor.smock
    FIXUP: JOSM-20040, fix restartless uninstall

    Several classes had to be modified to avoid NPE's, and the actual code
    to destroy menu items now has to account for null objects.

    Signed-off-by: Taylor Smock <tsmock@fb.com> (détails)
    by taylor.smock

[mdk]

It looks like all tests have the same reason to fail:

Invalid test class 'org.openstreetmap.josm.plugins.mapillary.utils.api.<test class>':
  1. The class org.openstreetmap.josm.plugins.mapillary.utils.api.<test class> is not public.
  2. Test class should have exactly one public constructor
  3. No runnable methods

[taylor.smock]

I need to make some modifications to build-common.xml, I think.

Issue:
build-common.xml is still using junit for running unit tests, and the ant junit task supports JUnit 3 and JUnit 4, but not JUnit 5.

Solution:
Switch to junitlauncher which supports JUnit 4 and JUnit 5 (and maybe JUnit 3 through the JUnit 4 support, I'll check with eventbus -- SubscriberTest.java seems to use JUnit 3). turnrestrictions also uses JUnit 3 in AllEditorTests.

[taylor.smock]

JUnit to JUnitLauncher for plugins

[Don-vip]

In 35642/osm:

see #16567 - see #20085 - JUnit to JUnitLauncher for plugins (patch by taylor.smock)