Simplify setStreamAndEndDelay in DelayedClientTransport per review comment

Author: AgraVator

core/src/main/java/io/grpc/internal/DelayedClientTransport.java

@@ -469,12 +469,7 @@ synchronized void endDelay() {
     }
 
     Runnable setStreamAndEndDelay(ClientStream stream) {
-      synchronized (this) {
-        if (getRealStream() != null) {
-          return null;
-        }
-        endDelay();
-      }
+      endDelay();
       return setStream(stream);
     }