Use after free in janet_sweep

With the following new fuzz target generated by https://github.com/google/oss-fuzz-gen: include include include int LLVMFuzzerTestOneInputconst uint8t data, sizet size / init Janet / janetinit; JanetTable env = janetcoreenvNULL; const char sourcePath = "fuzzdostring"; Janet out; if size 0 / Ensur...