fuzz-journal-stream: avoid assertion failure on samples which don't fit in pipe
    
    Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=11587.
    We had a sample which was large enough that write(2) failed to push all the
    data into the pipe, and an assert failed. The code could be changed to use
    a loop, but then we'd need to interleave writes and sd_event_run (to process
    the journal). I don't think the complexity is worth it — fuzzing works best
    if the sample is not too huge anyway. So let's just reject samples above 64k,
    and tell oss-fuzz about this limit.
    
    (cherry picked from commit eafadd069c4e30ed62173123326a7237448615d1)
    
    Resolves: #1764560
    
    patch_name: 0264-fuzz-journal-stream-avoid-assertion-failure-on-sampl.patch
    present_in_specfile: true
    location_in_specfile: 264
    squash_commits: true