[Nvfuser] Add cast support between double and half types
Fixes `RuntimeError: Illegal Cast value from DataType: __half to DataType: double`
Example:
```
with FusionDefinition(fusion) as fd :
t0 = fd.define_tensor(2, DataType.Half)
t1 = fd.define_tensor(2, DataType.Double)
fd.add_input(t0)
fd.add_input(t1)
t2 = fd.Ops.add(t0, t1)
t5 = fd.Ops.relu(t2)
fd.add_output(t5)
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/76605
Approved by: https://github.com/csarofeen
