COIN: Use dedicated platform configs for non-FFmpeg backend tests


The associated patch adds new platform-config targets for tests in CI.
This patch makes us run native media backend tests on those platforms.
This allows us to still run darwin and windows media backend tests,
but keep them separate in CI and separate the testresults when we gather
stats.

Pick-to: 6.12
Change-Id: I4a8f112a7e51d4976689c51adfbd9d6b9e1fd3f6
Reviewed-by: Tim Blechmann <tim.blechmann@qt.io>
commitf2ffa6b9f807b500ad137643c2bbf5f372afbb34
parent1f963638e008fb7d30bc213869a8806c6891037f
authorNils Petter Skålerud <nils.petter.skalerud@qt.io>
committerNils Petter Skålerud <nils.petter.skalerud@qt.io>
commit timeThu, 15 Oct 2026 11:18:50 +0000