MAINT: remove a dead code branch from test_nonzero

The branch is checking for x.ndim == 0, while the hypothesis
decorator only generates arrays of at least ndim=1:

`given(hh.arrays(dtype=hh.all_dtypes, shape=hh.shapes(min_dims=1, min_side=1)))`

This is consistent with the spec:
https://data-apis.org/array-api/draft/API_specification/generated/array_api.nonzero.html

> x (array) – input array. **Must** have one or more dimensions.
> If x is zero-dimensional, the function **must** raise an exception.

Author: ev-br

array_api_tests/test_searching_functions.py

@@ -180,19 +180,15 @@ def test_nonzero(x):
             for idx in sh.ndindex(x.shape):
                 if x[idx] != 0:
                     indices.append(idx)
-        if x.ndim == 0:
-            assert out_size == len(
-                indices
-            ), f"prod(out[0].shape)={out_size}, but should be {len(indices)}"
-        else:
-            for i in range(out_size):
-                idx = tuple(int(x[i]) for x in out)
-                f_idx = f"Extrapolated index (x[{i}] for x in out)={idx}"
-                f_element = f"x[{idx}]={x[idx]}"
-                assert idx in indices, f"{f_idx} results in {f_element}, a zero element"
-                assert (
-                    idx == indices[i]
-                ), f"{f_idx} is in the wrong position, should be {indices.index(idx)}"
+
+        for i in range(out_size):
+            idx = tuple(int(x[i]) for x in out)
+            f_idx = f"Extrapolated index (x[{i}] for x in out)={idx}"
+            f_element = f"x[{idx}]={x[idx]}"
+            assert idx in indices, f"{f_idx} results in {f_element}, a zero element"
+            assert (
+                idx == indices[i]
+            ), f"{f_idx} is in the wrong position, should be {indices.index(idx)}"
     except Exception as exc:
         ph.add_note(exc, repro_snippet)
         raise