The packet parsing parts should be covered by read handle.
Also need to try get a successful build on oss-fuzz, so these may be
re-enabled in the future.
These initialise the broker and leave it running. This is problematic
from the point of view of deterministic testing, but should mean the
testing speed is vastly improved.
If there is a real problem, the fuzz timeout should be invoked.
Fixes oss-fuzz #55667.
This was a bug in the fuzz target only, not in the code being
fuzzed.
Roger A. Light