Evas render: Fix double-clipping issue with maps

Evas render: Fix double-clipping issue with maps

Situation:
 - Evas Object A has a clip C and a map M.

Problem:
 - Clip C will be applied once inside the map surface S and
   again when the surface S is drawn to the canvas.

Solution:
 - Track whether the current object is the mapped object
   or a child of the mapped object. In the first case,
   discard the clipper when rendering to the map surface.
   In the second case, the child's clipper is PROBABLY[*]
   inside the map, so it should be applied when rendering the
   map surface itself.

Note: This also applies to masks.

[*] This is clearly not the ultimate clipping fix.