test_integration: Support external names for hosts

The framework had a concept of external hostnames,
which the controller uses to contact the test machines,
but they were not loaded from configuration.

Load external names from configuration.

This makes tests pass in setups where internal and external
hostnames are different, and the internal hostnames are not
initially resolvable from the controller.

ipatests/test_integration/config.py

@@ -236,8 +236,10 @@ def env_normalize(env):
     """Fill env variables from alternate variable names
 
     MASTER_env1 <- MASTER
-    REPLICA_env1 <- REPLICA
-    CLIENT_env1 <- CLIENT, SLAVE
+    REPLICA_env1 <- REPLICA, SLAVE
+    CLIENT_env1 <- CLIENT
+    similarly for BEAKER* variants: BEAKERMASTER1_env1 <- BEAKERMASTER, etc.
+
     CLIENT_env1 gets extended with CLIENT2 or CLIENT2_env1
     """
     def coalesce(name, *other_names):
@@ -253,8 +255,12 @@ def env_normalize(env):
             else:
                 env[name] = ''
     coalesce('MASTER_env1', 'MASTER')
-    coalesce('REPLICA_env1', 'REPLICA')
-    coalesce('CLIENT_env1', 'CLIENT', 'SLAVE')
+    coalesce('REPLICA_env1', 'REPLICA', 'SLAVE')
+    coalesce('CLIENT_env1', 'CLIENT')
+
+    coalesce('BEAKERMASTER1_env1', 'BEAKERMASTER')
+    coalesce('BEAKERREPLICA1_env1', 'BEAKERREPLICA', 'BEAKERSLAVE')
+    coalesce('BEAKERCLIENT1_env1', 'BEAKERCLIENT')
 
     def extend(name, name2):
         value = env.get(name2)