Ecto.Schema: Allow embedded_schema to have non-virtual :any fields

[wojtekmach]

No description provided.

[josevalim]

What if we store @ecto_source and then we check if it is nil? Loading all fields from attributes can get expensive.

We should also move the expensive check last:

Suggested change

	fields = Module.get_attribute(mod, :ecto_struct_fields)
	schema_with_source? = match?(%Ecto.Schema.Metadata{}, fields[:__meta__])
	if schema_with_source? && type == :any && !opts[:virtual] do
	if type == :any && !opts[:virtual] &&
	match?(%Ecto.Schema.Metadata{}, Module.get_attribute(mod, :ecto_struct_fields)[:__meta__]) do