Support for groups in conv-transpose1d. (#1731)

* Groups support in conv-transpose-1d.

* Remove dangling file.

candle-core/src/backprop.rs

@@ -250,6 +250,7 @@ impl Tensor {
                             out_padding,
                             *stride,
                             *dilation,
+                            /* groups */ 1,
                         )?;
                         let sum_grad = grads.or_insert(arg)?;
                         *sum_grad = sum_grad.add(&grad_arg)?;