Describe the bug
AFL_FRIDA_INST_UNSTABLE_COVERAGE_FILE is not always working, there seems to be a problem with something like a race condition, frida_mode is looking for fuzzer_stats while the file has not been created yet.

[-] PROGRAM ABORT : We need at least one valid input seed that does not crash!
         Location : main(), src/afl-fuzz.c:2743

with some prints and sleeps added to the relevant functions we had this error message:

[-] PROGRAM ABORT : Failed to read fuzzer_stats
         Location : instrument_coverage_unstable_read_unstable_ids(), src/instrument/instrument_coverage.c:497

To Reproduce
https://github.com/killerra/HelloWorldFuzz
make target in src dir and run fuzz.sh 2

Expected behavior
Output of a unstable coverage file without any errors