Revert changes to SelectorManager::shutdown

Author: dfuch

src/java.net.http/share/classes/jdk/internal/net/http/HttpClientImpl.java

@@ -1333,13 +1333,6 @@ String getName() {
 
         // Only called by the selector manager thread
         private void shutdown() {
-            // first stop the client to avoid seeing exceptions
-            // about "selector manager closed"
-            Log.logTrace("{0}: stopping", owner.dbgTag);
-            try {
-                owner.stop();
-            } catch (Throwable ignored) {
-            }
             try {
                 lock.lock();
                 try {
@@ -1352,7 +1345,6 @@ private void shutdown() {
                 }
             } catch (IOException ignored) {
             } finally {
-                // cleanup anything that might have been left behind
                 owner.stop();
             }
         }