geom ops suffix: query cache to see what the next suffix number should be

[caver456]

Currently, cutting A once, then cutting A again, will result in two A:1 shapes. Query the cache at the time of the geom op to set the starting index for suffixes, so that there will only be one A:1 and one A:2

[caver456]

This should still be done, but will probably not be relevant as often, since useResultNameSuffix defaults to False for crop (but True for cut). It does mean that trying to do geometry operations on a result of a crop operation will be ambiguous since all results will have the same name, but the workaround for that, if really needed, would be to change the name of the feature in question before trying the geom op.