The only users of more than one read- or write channel are the SCTP
code and QProcess. SCTP being pretty rare, optimize for the common
case of at most two QRingBuffers for reading (QProcess) and one for
writing. Even with more channels, QVLA shouldn't be slower than QList
- on the contrary.
Need to adjust tst_toolsupport and TypeInformationVersion, as
QFilePrivate::fileName has changed.
Pick-to: 6.3
Change-Id: I3baf982ba1f4dc51463be8730e414f6164072d8b
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
63a35898f4