[fuzzer][test] Add #include <cstdint> for gcc-13

See https://gcc.gnu.org/gcc-13/porting_to.html#header-dep-changes.

Reviewed By: SixWeining

Differential Revision: https://reviews.llvm.org/D137696

GitOrigin-RevId: 3ba498d145f7ce07b5c25633c2179e64943dae13
2 files changed