ddraw: Add local buffer in d3d_device7_DrawPrimitive()
Convert all consecutive calls to d7_DrawPrimitive(TRIANGLE_FAN) into a single call to d7_DrawPrimitive(TRIANGLE_LIST) with all the vertices.
Note, it increase the number of vertices, but bandwith is much less costly than multiple calls.
Note, only a very precise subset of the calls get buffered in order to ensure that the disruption is minimal.