When converting a graph to a module that came from MlirXlaOpKernel force the use of _output_shapes.
When converting a graph to a module that came from MlirXlaOpKernel force the use of _output_shapes.
When an Op is to be lowered by MlirXlaOpKernel all the output tensor shapes have been thrown away (except in the attribute) - this hasn't been a problem for most kernels because they generate the output shape based on inputs or other features; however, some Ops (e.g. _XlaHostComputeMlir') do not and are broken by the go/tuba bridge changes. This change forces the graph to module conv...

***

FUTURE_COPYBARA_INTEGRATE_REVIEW=https://github.com/openxla/xla/pull/9778 from shraiysh:flash-attn-2 77a644020c82939ea89c717c3490b5469d35e175
