De-select odd numbered heads from nn.MHA fastpath (#99672)
Summary:
https://github.com/pytorch/pytorch/issues/97128
* Add test for mha num_heads %2 != 0
* Fix test
* Add test for bias false
* show test passes
Test Plan: sandcastle
Differential Revision: D45161767
Pull Request resolved: https://github.com/pytorch/pytorch/pull/99672
Approved by: https://github.com/ngimel
