test: Run fuzz tests on macOS

Also, fix a few bugs:

* Error: RPC command "enumeratesigners" not found in RPC_COMMANDS_SAFE_FOR_FUZZING or RPC_COMMANDS_NOT_SAFE_FOR_FUZZING. Please update test/fuzz/rpc.cpp.
* in run_once: ...format(" ".join(result.args), ... TypeError: sequence item 2: expected str instance, PosixPath found

ci/test/00_setup_env_mac_native_arm64.sh

@@ -14,3 +14,5 @@ export CI_OS_NAME="macos"
 export NO_DEPENDS=1
 export OSX_SDK=""
 export CCACHE_SIZE=300M
+export RUN_FUZZ_TESTS=true
+export FUZZ_TESTS_CONFIG="--exclude banman"  # https://github.com/bitcoin/bitcoin/issues/27924