Prepare BTLE unit tests for platforms which don't provide handle access

Change-Id: I63a6d31aaa13bf94ef0cc9664dd365ddb1d84b52
Reviewed-by: Timur Pocheptsov <Timur.Pocheptsov@digia.com>
Reviewed-by: Alex Blasche <alexander.blasche@theqtcompany.com>
Fix test warning about missing meta type registration

Change-Id: I79970d1f460e2384b459a967405c849b5c0aae03
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@digia.com>
Reviewed-by: Timur Pocheptsov <Timur.Pocheptsov@digia.com>