[inductor] Handle aten.full's dtype in the decomposition (#108443)
In the lowering we don't have `SymFloat` and `SymInt`, we just have `sympy.Expr`
so it is impossible to accurately determine the expected dtype of a `full` call.
For example, `sym_float(int_expr)` has `is_integer=True` but should be treated
as a float. In the decomposition though, we can get this right.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/108443
Approved by: https://github.com/lezcano
