[libbpf] remove an out-of-date comment (#6931)
[libbpf] remove an out-of-date comment (#6931)

All the issues that check was supposed to catch should be
caught by the libbpf testsuite when it's run under UBSan
so it doesn't seem to make much sense to add it to the compiler
flags on OSS-Fuzz.
googlefonts/oss-fuzz,googlefonts/oss-fuzz,skia-dev/oss-fuzz,robertswiecki/oss-fuzz,robertswiecki/oss-fuzz,skia-dev/oss-fuzz,skia-dev/oss-fuzz,googlefonts/oss-fuzz,googlefonts/oss-fuzz,google/oss-fuzz,robertswiecki/oss-fuzz,robertswiecki/oss-fuzz,robertswiecki/oss-fuzz,google/oss-fuzz,googlefonts/oss-fuzz,skia-dev/oss-fuzz,robertswiecki/oss-fuzz,robertswiecki/oss-fuzz,skia-dev/oss-fuzz,google/oss-fuzz,google/oss-fuzz,googlefonts/oss-fuzz,google/oss-fuzz,googlefonts/oss-fuzz,robertswiecki/oss-fuzz,googlefonts/oss-fuzz,robertswiecki/oss-fuzz,google/oss-fuzz,googlefonts/oss-fuzz,google/oss-fuzz,google/oss-fuzz,google/oss-fuzz,skia-dev/oss-fuzz,google/oss-fuzz,skia-dev/oss-fuzz,skia-dev/oss-fuzz,skia-dev/oss-fuzz,robertswiecki/oss-fuzz,skia-dev/oss-fuzz,robertswiecki/oss-fuzz,googlefonts/oss-fuzz,skia-dev/oss-fuzz,google/oss-fuzz