extends the range of allowed dynamic payload types by the lower range [35, 63] from https://www.iana.org/assignments/rtp-parameters/rtp-parameters.xhtml#rtp-parameters-1 The upper limit of that range is chosen to avoid the payload types 64 and 65 which may conflict with RTCP as described in https://tools.ietf.org/html/rfc5761#section-4 A killswitch WebRTC-PayloadTypes-Lower-Dynamic-Range is added to allow turning this off should it result in interoperability issues. BUG=webrtc:12194 Change-Id: I7564cc190e4c18cd5b48510a5b6a467c13b0fae4 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/195821 Reviewed-by: Erik Språng <sprang@webrtc.org> Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org> Reviewed-by: Harald Alvestrand <hta@webrtc.org> Commit-Queue: Ilya Nikolaevskiy <ilnik@webrtc.org> Cr-Commit-Position: refs/heads/master@{#32790}