* Implement partial shape/type propagation for Convolution; fail for want of unit tests

* Implement unit tests for partial shapes/types for Convolution

* Implement partial shape/type validation for BatchNormInference, BatchNormTraining, BatchNormTrainingBackprop with unit tests

* Formatting

* Update CPU and GPU backends to deal with elimination of BatchNormBase

* Update BatchNormTrainingWithStats to use templated emit_BatchNorm function

* Restore five-argument BatchNormTraining ctor for now; #1901 will eliminate it

* Replace enum for input indices with symbolic constants

* Update intelgpu/visualize_tree.cpp to deal with removal of BatchNormBase