Changed Oracle test-user creation to grant privileges instead of roles

because the roles (specifically RESOURCE) are deprecated.
Also added optional support for creating views in tests, and made an
introspection test fail (rather than skip)  if a view cannot be created
due to lacking privileges.

Refs #18782

Thanks Tim Graham for review, and Josh Smeaton

tests/introspection/tests.py

@@ -43,7 +43,7 @@ class IntrospectionTests(TestCase):
                     'from introspection_article;')
             except DatabaseError as e:
                 if 'insufficient privileges' in str(e):
-                    self.skipTest("The test user has no CREATE VIEW privileges")
+                    self.fail("The test user has no CREATE VIEW privileges")
                 else:
                     raise