Use define_tables for IsOrIsNotDistinctFromTest

In Ie8127ef29f1ec91e7afb88e1429538c27a321784 Mike
failed to notice that this test is build on TablesTest and
has just the one test function, which means the table is
built up by the fixture.

Change-Id: I855431bc976fe8ec96559ec1a22bb294aecf3c40
(cherry picked from commit e228b41432)

lib/sqlalchemy/testing/suite/test_select.py

@@ -708,7 +708,16 @@ class IsOrIsNotDistinctFromTest(fixtures.TablesTest):
     __backend__ = True
     __requires__ = ("supports_is_distinct_from",)
 
-    @testing.provide_metadata
+    @classmethod
+    def define_tables(cls, metadata):
+        Table(
+            "is_distinct_test",
+            metadata,
+            Column("id", Integer, primary_key=True),
+            Column("col_a", Integer, nullable=True),
+            Column("col_b", Integer, nullable=True),
+        )
+
     @testing.combinations(
         ("both_int_different", 0, 1, 1),
         ("both_int_same", 1, 1, 0),
@@ -721,15 +730,8 @@ class IsOrIsNotDistinctFromTest(fixtures.TablesTest):
     def test_is_or_isnot_distinct_from(
         self, col_a_value, col_b_value, expected_row_count_for_is, connection
     ):
-        meta = self.metadata
-        tbl = Table(
-            "is_distinct_test",
-            meta,
-            Column("id", Integer, primary_key=True),
-            Column("col_a", Integer, nullable=True),
-            Column("col_b", Integer, nullable=True),
-        )
-        meta.create_all()
+        tbl = self.tables.is_distinct_test
+
         connection.execute(
             tbl.insert(),
             [{"id": 1, "col_a": col_a_value, "col_b": col_b_value}],