Debugger: require debugger to be active when dealing with breaks.

test/mjsunit/deserialize-script-id.js

Index: test/mjsunit/deserialize-script-id.js
diff --git a/test/mjsunit/deserialize-script-id.js b/test/mjsunit/deserialize-script-id.js
index ba54b4698eeafa555934954142c40c3cf0edd779..83658126bc072c530bf0895622065831ed9f9774 100644
--- a/test/mjsunit/deserialize-script-id.js
+++ b/test/mjsunit/deserialize-script-id.js
@@ -5,6 +5,9 @@
 // Flags: --allow-natives-syntax --cache=code
 // Test that script ids are unique and we found the correct ones.
 
+var Debug = %GetDebugContext().Debug;
+Debug.setListener(function(){});
+
 var scripts = %DebugGetLoadedScripts();
 scripts.sort(function(a, b) { return a.id - b.id; });
 var user_script_count = 0;
@@ -15,3 +18,5 @@ scripts.reduce(function(prev, cur) {
 
 // Found mjsunit.js and this script.
 assertEquals(2, user_script_count);
+
+Debug.setListener(null);