Fix bug method checkFeatureProjectionEquality

There was a typo in the method checkFeatureProjectionEquality() in class FeatureSerializerTestUtils that could lead to the wrong assumption the feature projections of the given feature were equal, while it could be the case that in fact they were not.

This commit fixes this typo.

src/test/java/org/mastodon/mamut/feature/FeatureSerializerTestUtils.java

@@ -105,7 +105,7 @@ public static < T > boolean checkFeatureProjectionEquality( Feature< T > feature
 		Map< FeatureProjectionKey, FeatureProjection< T > > projections1 = feature1.projections().stream()
 				.collect( Collectors.toMap( FeatureProjection::getKey, x -> x ) );
 
-		Map< FeatureProjectionKey, FeatureProjection< T > > projections2 = feature1.projections().stream()
+		Map< FeatureProjectionKey, FeatureProjection< T > > projections2 = feature2.projections().stream()
 				.collect( Collectors.toMap( FeatureProjection::getKey, x -> x ) );
 
 		if ( !projections1.keySet().equals( projections2.keySet() ) )