HBASE-27956 Support wall clock profiling in ProfilerServlet (#5337)

Signed-off-by: Reid Chan <reidchan@apache.org>

Author: bbeaudreault

hbase-http/src/main/java/org/apache/hadoop/hbase/http/ProfileServlet.java

@@ -74,6 +74,7 @@ public class ProfileServlet extends HttpServlet {
 
   enum Event {
     CPU("cpu"),
+    WALL("wall"),
     ALLOC("alloc"),
     LOCK("lock"),
     PAGE_FAULTS("page-faults"),