Steps to reproduce:
1. generate docs for the mainline jdk project (make jdk-image docs)
2. checkout the http3 branch in a clone of the jdk-sandbox project and generate docs for the branch: (make jdk-image docs)
3. set java to the generated mainline jdk image
4. run apidiff from the sandbox repo:
apidiff --api jdk24 --api-directory ../jdk-dev-git/build/macosx-aarch64/images/docs/api --api http3 --api-directory ./build/macosx-aarch64/images/docs/api -d build/apidiff-http3 --include 'java.net.http/**' --verbose all

Among others:
 - The changes in java.net.http.HttpClient.Version are not found
 - The changes in java.net.http.HttpRequest and java.net.http.HttpRequest.Builder are not found