[clang] [clang-fuzzer-dictionary] Fix build failure with libfuzzer (PR #99871)

[Raphael Isemann via cfe-commits]

Teemperor wrote:

FWIW, this dictionary is (at least was supposed) to be used by oss-fuzz, but because of the build issue it's [disabled since about 2 years](https://github.com/google/oss-fuzz/blob/7c41fbc6e984df411981e3c9a4b47a573cd327ea/projects/llvm/build.sh#L183)

https://github.com/llvm/llvm-project/pull/99871