Compatibility mode broken with oss-fuzz

[vrabaud]

Two recent commits prevent us from upgrading fuzztest as our dependency for our fuzztest tests built on oss-fuzz as they break the check_build python3 infra/helper.py check_build --sanitizer address libavif.

The first one is: c217c31 . The change in

fuzztest/fuzztest/internal/compatibility_mode.cc

Line 128 in a990537

if (IsEnginePlaceholderInput(data)) return;

gets it to fail and we have to modify it to if (data.size() == 0) return;. I am not sure on whether it makes sense though.

The second one is 0c80b31 but it is not because of the bumped dependencies, it is because of set(GTEST_HAS_ABSL ON) which forces gtest to use absl flags and apparently has a different parsing. Before that, we could send flags to libfuzzer (deprecated but used on oss-fuzz) the following way: ./test --fuzz=MyTest -- -seed=0 -timeout=10 (here https://github.com/AOMediaCodec/libavif/blob/d074bae4b0b1d7423d102f6d9d5e0c5303971a51/tests/oss-fuzz/build.sh#L123) as officially done upstream at https://github.com/google/oss-fuzz/blob/50c8bb586c0835e6fda39e7e933be197750cdf03/infra/base-images/base-builder/compile_fuzztests.sh#L77