Reset jitter buffer after Opus ptime decreased

[nanang]

When inserting a frame to JB, the stream assigns index for the frame using this kind of formula (not exactly): RTP-timestamp/ptime, so when ptime is increasing (i.e: doubled from 20ms to 40ms), frame indexes suddenly get much smaller (about half), and JB will see it as "sequence restart" (note that if the index difference is less than 100, JB will see it just as late frame). So basically the stream formula does not work well with ptime change, and modifying that behavior seems to be quite a major change. So resetting jitter buffer should be practical workaround. Note that actually the stream also resets the JB when seeing G722/MPEG timestamp span change.

Thanks Marcus Froeschl for the report.

[nanang]

In 6043:

Fix #2215:

• Reset jitter buffer after Opus ptime decreased.
• Updated jitter buffer framelist sequence restart detection, also added some tracing logs.