OSV-2022-222 Heap-use-after-free in cb_stdout_flush

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=45251 Crash type: Heap-use-after-free READ Crash state: cbstdoutflush outputprecbflush flb-it-fuzz-filterstdoutfuzzerOSSFUZZ...