Fixes #86178 by hiding the GMap Terrain base layer as soon its tiles load. At that poing the GMap div was added independetly of the layer's visibility. Should also fix any other problem related to the existence of a "ghost" base layer.
Merge pull request #211 from luisromangz/8.5-SNAPSHOT-86178

Fixes #86178 by hiding the GMap Terrain base layer as soon its tiles are loaded