[PATCH] Don't ValidateTree/expose when changing the input shape

[Pierre-Loup A. Griffais]

ValidateTree can be pretty expensive; gnome-shell floods the server with input 
shape requests when animating windows, so that change makes it perform a lot better.

Aaron suggested Keith and Adam as reviewers; are the SetWinSize, SetBorderSize, 
ResizeChildrenWinSize also unneeded when changing the input shape? The only 
thing that looks needed for sure is CheckCursorConfinement(), but I have my 
doubts about the rest.

Thanks,
  - Pierre-Loup