Fix java-http-client tests

[jaydeluca]

While working on #13468 I noticed these tests weren't emitting metrics like I was expecting. It seems that at least for me locally, these tests are failing to run but not being counted as a failed test run.

I found that running ./gradlew :instrumentation:java-http-client:javaagent:test resulted in:

(2) [WARNING] @Nested class 'io.opentelemetry.javaagent.instrumentation.javahttpclient.JavaHttpClientTest$Http2ClientTest' must not be static. It will not be executed.
    Source: ClassSource [className = 'io.opentelemetry.javaagent.instrumentation.javahttpclient.JavaHttpClientTest$Http2ClientTest', filePosition = null]
            at io.opentelemetry.javaagent.instrumentation.javahttpclient.JavaHttpClientTest$Http2ClientTest.<no-method>(SourceFile:0)

[laurit]

Probably stopped working with the latest junit update. The same test is also present in library module. Did you consider just removing the static from the nested class? If removing static doesn't work the we should also test the other @Nested tests.

[jaydeluca]

removing static does not fix it, although it makes that particular error message go away. It just silently doesn't run any tests. I will take a look at other tests that might use nested

[jaydeluca]

I tested making these classes non-static, but then I hit circular dependency with the inner class extending its enclosing class

If we keep the classes static and remove the @Nested annotation, the tests run, but I believe that we risk test isolation problems

[laurit]

Nested tests could be made to work with #14043 Honestly I'm not sure which I like better.

[laurit]

resolved with #14043