abbreviate flattening and sorting of second argument in isin

Author: ndgrigorian

dpctl/tensor/_set_functions.py

@@ -747,8 +747,8 @@ def isin(x, test_elements, /, *, invert=False):
     else:
         test_buf = test_arr
 
-    test_buf = dpt.reshape(test_buf, -1)
-    test_buf = dpt.sort(test_buf)
+    # flatten and sort
+    test_buf = dpt.sort(dpt.reshape(test_buf, -1))
 
     dst = dpt.empty_like(
         x_buf, dtype=dpt.bool, usm_type=res_usm_type, order="C"