Extend fuzzing tests

Test all combinations with/without `PL7M_USE_INTERNAL_FUZZER_MUTATE` and
`PL7M_USE_SIMPLEST_MUTATOR` defines

Author: IvanNardi

.github/workflows/build.yml

@@ -29,3 +29,9 @@ jobs:
           cd ../fuzz
           make clean && make
           ./run-fuzzer.sh
+          make clean && CFLAGS="-DPL7M_USE_INTERNAL_FUZZER_MUTATE -DPL7M_USE_SIMPLEST_MUTATOR" make
+          ./run-fuzzer.sh
+          make clean && CFLAGS="-DPL7M_USE_INTERNAL_FUZZER_MUTATE" make
+          ./run-fuzzer.sh
+          make clean && CFLAGS="-DPL7M_USE_SIMPLEST_MUTATOR" make
+          ./run-fuzzer.sh