[inspector] fixed crash on attempt to access empty scope_info on break

test/inspector/protocol-test.js

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 InspectorTest = {};
 InspectorTest._dispatchTable = new Map();
 InspectorTest._requestId = 0;
 InspectorTest._dumpInspectorProtocolMessages = false;
 InspectorTest._eventHandler = {};
 
@@ skipping 116 matching lines @@
       .then(dumpSourceWithLocation);
   }
   return Promise.resolve().then(dumpSourceWithLocation);
 
   function dumpSourceWithLocation() {
     var location = callFrame.location;
     var lines = script.scriptSource.split('\n');
     var line = lines[location.lineNumber];
     line = line.slice(0, location.columnNumber) + '#' + (line.slice(location.columnNumber) || '');
     lines[location.lineNumber] = line;
+    lines = lines.filter(line => line.indexOf('//# sourceURL=') === -1);
     InspectorTest.log(lines.slice(Math.max(location.lineNumber - 1, 0), location.lineNumber + 2).join('\n'));
     InspectorTest.log('');
   }
 }
 
 InspectorTest.logAsyncStackTrace = function(asyncStackTrace)
 {
   while (asyncStackTrace) {
     if (asyncStackTrace.promiseCreationFrame) {
       var frame = asyncStackTrace.promiseCreationFrame;
@@ skipping 119 matching lines @@
     }
   } catch (e) {
     InspectorTest.log("Exception when dispatching message: " + e + "\n" + e.stack + "\n message = " + JSON.stringify(messageObject, null, 2));
     InspectorTest.completeTest();
   }
 }
 
 InspectorTest.loadScript = function(fileName) {
   InspectorTest.addScript(read(fileName));
 }