The run-test-server.sh exits immediately
After changing to using daemon threads by default, this script stopped working.  We need to update the server to keep alive until cancelled (e.g. ctrl+c).

diff --git a/interop-testing/src/main/java/io/grpc/testing/integration/TestServiceServer.java b/interop-testing/src/main/java/io/grpc/testing/integration/TestServiceServer.java
index 07ebefec6..f994c2cd5 100644
--- a/interop-testing/src/main/java/io/grpc/testing/integration/TestServiceServer.java
+++ b/interop-testing/src/main/java/io/grpc/testing/integration/TestServiceServer.java
@@ -74,6 +74,7 @@ public class TestServiceServer {
     });
     server.start();
     System.out.println("Server started on port " + server.port);
+    server.blockUntilShutdown();
   }
 
   private int port = 8080;
@@ -152,4 +153,13 @@ public class TestServiceServer {
     }
     MoreExecutors.shutdownAndAwaitTermination(executor, 5, TimeUnit.SECONDS);
   }
+
+  /**
+   * Await termination on the main thread since the grpc library uses daemon threads.
+   */
+  private void blockUntilShutdown() throws InterruptedException {
+    if (server != null) {
+      server.awaitTermination();
+    }
+  }
 }
['interop-testing/src/main/java/io/grpc/testing/integration/TestServiceServer.java']