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

test/mjsunit/regress/regress-debug-code-recompilation.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 11 matching lines @@
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // Flags: --allow-natives-syntax --hydrogen-filter=Debug.setBreakPoint
 // Flags: --expose-debug-as debug
 
 Debug = debug.Debug
+Debug.setListener(function(){});
 
 function f() {a=1;b=2};
 function g() {
   a=1;
   b=2;
 }
 
 bp = Debug.setBreakPoint(f, 0, 0);
 Debug.clearBreakPoint(bp);
 %OptimizeFunctionOnNextCall(Debug.setBreakPoint);
 bp = Debug.setBreakPoint(f, 0, 0);
 Debug.clearBreakPoint(bp);
 bp = Debug.setBreakPoint(f, 0, 0);
 Debug.clearBreakPoint(bp);
 %OptimizeFunctionOnNextCall(Debug.setBreakPoint);
 bp = Debug.setBreakPoint(f, 0, 0);
 Debug.clearBreakPoint(bp);
+
+Debug.setListener(null);