Do not store CodeLocations in JSSourceValue objects.

The information is partly redundant, as we already know the file path.
Set only line and column info instead. This lowers peak memory use by
~2% with little effort.

Change-Id: I7c8b34aa9a026a6e8cf3d06e5caef5ceeae11270
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>