[kernel] Add offset to SwitchContinueStatement; add debugging test

pkg/kernel/lib/binary/ast_from_binary.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 library kernel.ast_from_binary;
 
 import 'dart:convert';
 import 'dart:typed_data';
 
 import '../ast.dart';
 import '../transformations/flags.dart';
@@ skipping 1049 matching lines @@
           for (int i = 0; i < length; ++i) {
             caseNode.expressionOffsets[i] = readOffset();
             caseNode.expressions[i] = readExpression()..parent = caseNode;
           }
           caseNode.isDefault = readByte() == 1;
           caseNode.body = readStatement()..parent = caseNode;
         }
         switchCaseStack.length -= count;
         return new SwitchStatement(expression, cases)..fileOffset = offset;
       case Tag.ContinueSwitchStatement:
+        int offset = readOffset();
         int index = readUInt();
-        return new ContinueSwitchStatement(switchCaseStack[index]);
+        return new ContinueSwitchStatement(switchCaseStack[index])
+          ..fileOffset = offset;
       case Tag.IfStatement:
         return new IfStatement(
             readExpression(), readStatement(), readStatementOrNullIfEmpty());
       case Tag.ReturnStatement:
         int offset = readOffset();
         return new ReturnStatement(readExpressionOption())..fileOffset = offset;
       case Tag.TryCatch:
         Statement body = readStatement();
         readByte(); // whether any catch needs a stacktrace.
         return new TryCatch(body, readCatchList());
@@ skipping 196 matching lines @@
       ..fileOffset = offset
       ..fileEqualsOffset = fileEqualsOffset;
   }
 
   int readOffset() {
     // Offset is saved as unsigned,
     // but actually ranges from -1 and up (thus the -1)
     return readUInt() - 1;
   }
 }