rtpsource: fix receiver source stats to consider previously queued packets

When it is not clear yet if a packet relative to a source should be
pushed, the packet is put into a queue, this happens in two cases:

  - the source is still in probation;
  - there is a large jump in seqnum, and it is not clear what
    the cause is, future packets will help making a guess.

In either case stats about received packets are not updated at all; and
even if they were, when init_seq() is called it resets all receiver
stats, effectively loosing any possible stat about previously received
packets.

Fix this by taking into account the queued packets and update the stats
when calling init_seq().
13 jobs for rtpsource-fix-stats-for-queued-packets in 62 minutes and 4 seconds (queued for 1 second)
Status Job ID Name Coverage
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passed #224745
gst indent

00:00:39

passed #224744
manifest

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  Build
passed #224746
build fedora x86_64

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passed #224747
build nodebug fedora x86_64

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  Test
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check fedora

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passed #224749
integration testsuites fedora

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build cerbero android universal

00:24:25

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build cerbero cross win32

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passed #224753
build cerbero cross win64

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passed #224750
build cerbero fedora x86_64

00:10:59

 
  Full Tests
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valgrind bad

00:07:56

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valgrind good

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android universal examples

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