Remove unnecessary checkout steps

[cmeister2]

No description provided.

[cmeister2]

Running the job reveals:

Running: docker run --rm --privileged --shm-size=2g --platform linux/amd64 -e 
FUZZING_ENGINE=libfuzzer -e CIFUZZ=True -e SANITIZER=address -e ARCHITECTURE=x86_64 
-e FUZZING_LANGUAGE=c++ -e OUT=/github/workspace/build-out --volumes-from 69676f1feb8b 
gcr.io/oss-fuzz/curl /bin/bash -c 'cp -r /src/curl_fuzzer /github/workspace/storage/curl_fuzzer'.

and

Running: docker run --rm --privileged --shm-size=2g --platform linux/amd64 -e 
FUZZING_ENGINE=libfuzzer -e CIFUZZ=True -e SANITIZER=address -e ARCHITECTURE=x86_64 
-e FUZZING_LANGUAGE=c++ -e OUT=/github/workspace/build-out --volumes-from 69676f1feb8b 
gcr.io/oss-fuzz/curl /bin/bash -c 'cd / && rm -rf /src/curl_fuzzer/* && cp -r /github/workspace/storage/curl_fuzzer /src && cd - && compile'.

Not entirely sure where the project-src-path is coming into play yet...

[cmeister2]

It seems as if the project-src-path is unnecessary because of the magic CIFuzz code which maps in the current repository correctly for both curl and curl-fuzzer (very impressive). This PR now removes the unnecessary checkouts