Move back-tranform of pre-transformed vertices to postTransform.
Move back-tranform of pre-transformed vertices to postTransform.

Bug 22624951

Change-Id: Ib8dfda6ed983f385a236b014d9b635a0c343071f
Reviewed-on: https://swiftshader-review.googlesource.com/3741
Tested-by: Nicolas Capens <0612353e1fcebbfd4b302d9337447ca0cdfa9122@google.com>
Reviewed-by: Alexis Hétu <1c7141772178a7e80858c3db5052b328076f08f4@google.com>
Reviewed-by: Nicolas Capens <0612353e1fcebbfd4b302d9337447ca0cdfa9122@google.com>

google/swiftshader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader