default scaling window is not set from conformance window in SPS

[furban]

(i) if required, the encoder computes an automatic conformance window signaled in SPS, but the scaling window is not set accordingly
(ii) the decoder can derive default scaling window from PPS conformance window, but not from SPS conformance widow when it is not present in PPS.

This has impact in multi-layer scalable encoding. As the bug is both in encoder and decoder the decoded MD5 look good, but there is a performance loss and mismatch with spec.

We are currently working on a fix and we will do a merge request

[delagrangep]

Merge request is !2122