Use EISOP release and include jspecify/jdk in jar

[wmdietl]

To test, include the changes from #178 and #186:

git clone https://github.com/jspecify/jspecify-reference-checker -b use-eisop-release
cd jspecify-reference-checker
git pull origin detailed-diagnostics --no-rebase
git pull origin issue-177 --no-rebase
./gradlew test conformanceTests

Everything should pass. The Basic.java conformance test would fail if it would not use jspecify/jdk.

I haven't tried including local checker-framework and jspecify clones, but would hope that that works as expected.

I'm trying to make a reference checker release and include it in a separate build, but will do that in a separate PR.