Update Skip class in CF-jdk8u40 to use a class from Java 11

Author: nr-kateanderson

instrumentation/java.completable-future-jdk8u40/src/main/java/java/util/concurrent/Skip_Flow.java

@@ -0,0 +1,12 @@
+package skip;
+
+import com.newrelic.api.agent.weaver.SkipIfPresent;
+
+/**
+ * This Skip class instructs JREs 11 and up to skip this instrumentation module,
+ * and use java.completable-future-jdk11 instead.
+ * HttpClient was chosen for the Skip because it was introduced with Java 11.
+ */
+@SkipIfPresent(originalName = "java.net.http.HttpClient")
+public class Skip_HttpClient {
+}