tests/test-fuzz-targets.t

wireprotov2peer: properly format errors

formatrichmessage() expects an iterable containing dicts with
well-defined keys. We were passing in something else. This caused
an exception.

Change the code to call formatrichmessage() with the proper argument.

And add a TODO to potentially emit the proper data structure from
the server in the first place.

Differential Revision: https://phab.mercurial-scm.org/D4441

#require test-repo

  $ cd $TESTDIR/../contrib/fuzz

#if clang-libfuzzer
  $ make -s clean all
#endif
#if no-clang-libfuzzer clang-6.0
  $ make -s clean all CC=clang-6.0 CXX=clang++-6.0
#endif
#if no-clang-libfuzzer no-clang-6.0
  $ exit 80
#endif

Just run the fuzzers for five seconds each to verify it works at all.
  $ ./bdiff -max_total_time 5
  $ ./mpatch -max_total_time 5
  $ ./xdiff -max_total_time 5