MgMap fails to initialize properly from linked tile set if both coordinate systems match

[jng]

When attempting to view a Map Definition that is linked to a tile set in the AJAX Viewer, the viewer will fail to load due to a null map extent.

The reason we have a null map extent is because when we initialize an MgMap from a Map Definition that links to a tile set, if both coordinate systems are the same, we are forgetting to set the map/data extents and center members, which results in a null map extent when retrieved.

The AJAX viewers tries to set up the initial view based on the extent of the map, which given it is null in this case causes the viewer loading to fail.

[jng]

Fixed r8548