COMPAT: 32-bit indexer (#18149)

xref #17755

Author: jreback

pandas/tests/indexes/period/test_indexing.py

@@ -501,7 +501,7 @@ def test_get_indexer_non_unique(self):
 
         result = idx1.get_indexer_non_unique(idx2)
         expected_indexer = np.array([1, 0, 2, -1, -1], dtype=np.intp)
-        expected_missing = np.array([2, 3], dtype=np.intp)
+        expected_missing = np.array([2, 3], dtype=np.int64)
 
         tm.assert_numpy_array_equal(result[0], expected_indexer)
         tm.assert_numpy_array_equal(result[1], expected_missing)