mesa: refine the error checking vbo_exec_DrawRangeElements()

mesa: refine the error checking vbo_exec_DrawRangeElements()

If the 'end' index is out of bounds issue a warning as before.  But instead
of just no-op'ing the draw call, examine the actual array indices to see
if they're OK.  If the max array index is out of bounds, issue another
warning and no-op the draw call.  Otherwise, draw normally.  This is a
debug build-only feature since it could impact performance.

This "fixes" the missing torus in the OGL Distilled / Picking demo.