android-maps-utils Unignore tests that should run on Robolectric

Is your feature request related to a problem? Please describe. In https://github.com/googlemaps/android-maps-utils/pull/649 we changed from using an emulator on Travis to using Robolectric CI, which means that all instrumented tests that were previously in the androidTest folder got moved to the test folder so they run on the JVM instead of an Android device or emulator.

In the first implementation of Robolectric in https://github.com/googlemaps/android-maps-utils/pull/649, we had to ignore some tests that failed on Robolectric - these are all currently annotated with @Ignore.

Describe the solution you'd like We should try and get the ignored tests running on Robolectric.

Here are tests that we should try to get running first, which previously ran on the emulator on Travis:

KmlContainerParserTest - entire class

These tests would be nice-to-have, although they were already skipped on the emulator on Travis because of existing issues:

GeoJsonPointStyleTest.testIcon()
KmlStyleTest.testMarkerColorLeadingSpace()
KmlStyleTest.testMarkerColorTrailingSpace()

Describe alternatives you've considered

Do nothing - continue to ignore the tests
Try out Firebase Test Lab - https://firebase.google.com/docs/test-lab

Additional context https://github.com/googlemaps/android-maps-utils/pull/649 contains some notes in the comments for issues I ran into when implementing Robolectric.

https://github.com/googlemaps/android-maps-utils/pull/573 contains some notes on why the nice-to-have tests were failing on the emulator on Travis.