IOT-2355: Change IPCA unit test agressive timeout.

IOT-2355: Change IPCA unit test agressive timeout.

https://jira.iotivity.org/browse/IOT-2355

The IPCA unit test "IsIoTivityWorking" has failed sporadically.
This test directly uses IoTivity OC APIs to ensure that the underlying
IoTivity stack is working.
The 2 second timeout is incorrect, it should follow RFC 7252.

Change-Id: Iff640c2dbc2423e4865a4d2c8856a766d5345fa4
Signed-off-by: Soemin Tjong <stjong@microsoft.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/20375
Reviewed-by: Phil Coval <philippe.coval@osg.samsung.com>
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Dan Mihai <Daniel.Mihai@microsoft.com>