Don't use cx_Oracle.NATIVE_INT in output type handlers

Don't use cx_Oracle.NATIVE_INT in output type handlers

Fixed regression in integer precision logic due to the refactor of the
cx_Oracle dialect in 1.2.  We now no longer apply the cx_Oracle.NATIVE_INT
type to result columns sending integer values (detected as positive
precision with scale ==0) which encounters integer overflow issues with
values that go beyond the 32 bit boundary.  Instead, the output variable
is left untyped so that cx_Oracle can choose the best option.

Fixes: #4457
Change-Id: I1e3114c2f37bf028fb1f521a3e9789a77e3a7491