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 conversion to use the _output_shapes attribute, if present, to reintroduce the Op's shape.
