Bump up the time we are willing to wait for gRPC to start up in GrpcServerTests.

Our Jenkins slaves are apparently slower than our workstations, thus, they are timeout-flaky.

--
PiperOrigin-RevId: 147590913
MOS_MIGRATED_REVID=147590913
diff --git a/src/test/java/com/google/devtools/build/lib/server/GrpcServerTest.java b/src/test/java/com/google/devtools/build/lib/server/GrpcServerTest.java
index cfb6b5c..b83ad04 100644
--- a/src/test/java/com/google/devtools/build/lib/server/GrpcServerTest.java
+++ b/src/test/java/com/google/devtools/build/lib/server/GrpcServerTest.java
@@ -380,8 +380,8 @@
       boolean ok = false;
 
       // Wait until the server starts up. Should be reasonably quick.
-      for (int i = 0; i < 20; i++) {
-        Thread.sleep(100);
+      for (int i = 0; i < 50; i++) {
+        Thread.sleep(200);
         PingRequest request = PingRequest.newBuilder()
             .setCookie(impl.getRequestCookie())
             .build();