PR #11478: [XLA:GPU] add guards for flash attention graph with cuDNN >= 8.9.4
PR #11478: [XLA:GPU] add guards for flash attention graph with cuDNN >= 8.9.4

Imported from GitHub PR https://github.com/openxla/xla/pull/11478

* Build XLA with cuDNN 8.6 will cause compilation error because flash attention graph will use `CudnnfMHAUid` which is only defined with cuDNN > 8.8.
* Add a guard for flash attention graph with at least cuDNN 8.9.4. So the current logic would be only compile FMHA with cuDNN > 8.8 and only compile flash attention with cuDNN > 8.9.4. 
Copybara import of the project:

--
a1aa585f4e6ce42c7486336549447151cd5f7690 by cjkkkk <ske@nvidia.com>:

add guards for flash attention graph with at least 8.9.4

Merging this change closes #11478

FUTURE_COPYBARA_INTEGRATE_REVIEW=https://github.com/openxla/xla/pull/11478 from Cjkkkk:fix_cudnn_8_6 a1aa585f4e6ce42c7486336549447151cd5f7690
