Fix IntegrationTestingTutorial network map race condition (#947)

* Ignoring and adding a TODO to a test that fails spuriously during CI.

* Ensure both parties are regsitered with network map in the integration test tutorial and update docs to reflect this best practice.

* Minor readability fix.

docs/source/example-code/src/integration-test/kotlin/net/corda/docs/IntegrationTestingTutorial.kt

@@ -51,6 +51,9 @@ class IntegrationTestingTutorial {
 
             val bobClient = bob.rpcClientToNode()
             val bobProxy = bobClient.start("bobUser", "testPassword2").proxy
+
+            aliceProxy.waitUntilRegisteredWithNetworkMap().getOrThrow()
+            bobProxy.waitUntilRegisteredWithNetworkMap().getOrThrow()
             // END 2
 
             // START 3

docs/source/tutorial-integration-testing.rst

@@ -35,7 +35,9 @@ notary directly, so there's no need to pass in the test ``User``.
 The ``startNode`` function returns a future that completes once the
 node is fully started. This allows starting of the nodes to be
 parallel. We wait on these futures as we need the information
-returned; their respective ``NodeHandles`` s.
+returned; their respective ``NodeHandles`` s. After getting the handles we
+wait for both parties to register with the network map to ensure we don't
+have race conditions with network map registration.
 
 .. literalinclude:: example-code/src/integration-test/kotlin/net/corda/docs/IntegrationTestingTutorial.kt
     :language: kotlin