[quant] Move dropout replacement to `move_model_to_eval` (#108184)
Summary: This commit adds a public facing
`torch.ao.quantization.move_model_to_eval` util function
for QAT users. Instead of calling model.eval() on an exported
model (which doesn't work, see
https://github.com/pytorch/pytorch/issues/103681), the user
would call this new util function instead. This ensures special
ops such as dropout and batchnorm (not supported yet) will have
the right behavior when the graph is later used for inference.
Note: Support for an equivalent `move_model_to_train` will be
added in the future. This is difficult to do for dropout
currently because the eval pattern of dropout is simply a clone
op, which we cannot just match and replace with a dropout op.
Test Plan:
python test/test_quantization.py TestQuantizePT2E.test_move_model_to_eval
Reviewers: jerryzh168, kimishpatel
Subscribers: jerryzh168, kimishpatel, supriyar
Differential Revision: [D48814735](https://our.internmc.facebook.com/intern/diff/D48814735)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/108184
Approved by: https://github.com/jerryzh168
