scripts/replay-dump.py: replay log dumper

scripts/replay-dump.py: replay log dumper

This script is a debugging tool for looking through the contents of a
replay log file. It is incomplete but should fail gracefully at events
it doesn't understand.

It currently understands two different log formats as the audio
record/replay support was merged during since MTTCG. It was written to
help debug what has caused the BQL changes to break replay support.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20180227095310.1060.14500.stgit@pasha-VirtualBox>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>