Remove ApacheClientNullHttpHostRequestTest

Apache HttpClient 4.0's DefaultRequestDirector.determineRoute throws
IllegalStateException when target host is null and not set in params,
so this test could never pass against the pinned 4.0 client. The
@nullable annotation added to the instrumentation advice is a
documentation-only change and does not need a runtime test.

Author: trask

instrumentation/apache-httpclient/apache-httpclient-4.0/javaagent/src/test/java/io/opentelemetry/javaagent/instrumentation/apachehttpclient/v4_0/ApacheHttpClientTest.java

@@ -93,25 +93,6 @@ void executeRequestWithCallback(BasicHttpRequest request, URI uri, HttpClientRes
     }
   }
 
-  @Nested
-  class ApacheClientNullHttpHostRequestTest extends AbstractTest<BasicHttpRequest> {
-    @Override
-    BasicHttpRequest createRequest(String method, URI uri) {
-      return new BasicHttpRequest(method, uri.toString());
-    }
-
-    @Override
-    HttpResponse doExecuteRequest(BasicHttpRequest request, URI uri) throws Exception {
-      return getClient(uri).execute(null, request);
-    }
-
-    @Override
-    void executeRequestWithCallback(BasicHttpRequest request, URI uri, HttpClientResult result)
-        throws Exception {
-      getClient(uri).execute(null, request, new HttpResponseHandler(result));
-    }
-  }
-
   @Nested
   class ApacheClientHostAbsoluteUriRequestTest extends AbstractTest<BasicHttpRequest> {
     @Override