btest: Use Broker for Broker specific tests

Now that Cluster::backend defaults to NONE by default, some tests won't
just work anymore for various reasons (mostly due to the logging
framework not sending log writes to broker anymore).

Load the new frameworks/cluster/backend/broker package for these to keep them
functional. Also add the @load to the common broker/cluster-layout.zeek file
to avoid changing all of the files that use that layout.

testing/btest/scripts/base/frameworks/control/configuration_update.zeek

@@ -5,6 +5,8 @@
 # @TEST-EXEC: btest-bg-wait 30
 # @TEST-EXEC: btest-diff controllee/.stdout
 
+@load frameworks/cluster/backend/broker
+
 @load base/frameworks/control
 
 const test_var = "ORIGINAL VALUE (this should be printed out first)" &redef;

testing/btest/scripts/base/frameworks/control/id_value.zeek

@@ -9,6 +9,8 @@
 # @TEST-EXEC: btest-bg-wait 30
 # @TEST-EXEC: btest-diff controller/.stdout
 
+@load frameworks/cluster/backend/broker
+
 @load base/frameworks/control
 
 # This value shouldn't ever be printed to the controllers stdout.

testing/btest/scripts/base/frameworks/control/shutdown.zeek

@@ -4,3 +4,5 @@
 # @TEST-EXEC: btest-bg-run controller ZEEKPATH=$ZEEKPATH:.. zeek -b %INPUT frameworks/control/controller Control::host=127.0.0.1 Control::host_port=$BROKER_PORT Control::cmd=shutdown
 # @TEST-EXEC: btest-bg-wait 20
 
+@load frameworks/cluster/backend/broker
+

testing/btest/scripts/base/frameworks/logging/length-checking.zeek

@@ -17,6 +17,9 @@
 # @TEST-START-FILE common.zeek
 @load base/frameworks/notice/weird
 
+# Ensure logging is done via Broker
+@load frameworks/cluster/backend/broker
+
 module Test;
 
 # Disable the string and container length filtering.