Split up Android builds by architecture

Split up Android builds by architecture

With the additional option of building Android for the x86_64
architecture builds can reach upwards of 3 hours. This change sets the
groundwork for adding the x86_64 arch as a build target by splitting up
the android build by architecture.

Change-Id: I8d6837c3187e871543c0841638d1cc50600f75a9
Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>
Reviewed-on: https://gerrit.iotivity.org/gerrit/2245
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Jon A. Cruz <jonc@osg.samsung.com>