testsuite: improve test_src_player speed

On a high end processor, test_src_player is taking a very long time:

./test_src_player  0.72s user 0.17s system 10% cpu 8.900 total

It's one of the longest test in the suite.

changed milestone to %Features paradize

added Component::Test label

It does not depend on processor speed since this test is mainly waiting.

I don't know how it is possible to test everything with less time...

Yes, but even though it's complex currently, I think that since we can have control over the demux and don't even care about the playback itself, but instead just the demux/es_out/player interactions, we shouldn't spend that much time waiting and instead run the whole test at 100% speed.