YARN-4555. TestDefaultContainerExecutor#testContainerLaunchError fails on non-english locale environment. Contributed by Takashi Ohnishi.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/TestDefaultContainerExecutor.java

@@ -268,6 +268,7 @@ public class TestDefaultContainerExecutor {
     ContainerId cId = mock(ContainerId.class);
     ContainerLaunchContext context = mock(ContainerLaunchContext.class);
     HashMap<String, String> env = new HashMap<String, String>();
+    env.put("LANG", "C");
 
     when(container.getContainerId()).thenReturn(cId);
     when(container.getLaunchContext()).thenReturn(context);