[kernel] Add offset to SwitchContinueStatement; add debugging test

pkg/kernel/lib/binary/ast_from_binary.dart

Index: pkg/kernel/lib/binary/ast_from_binary.dart
diff --git a/pkg/kernel/lib/binary/ast_from_binary.dart b/pkg/kernel/lib/binary/ast_from_binary.dart
index 449292e00d21bf288190acd0366adf3458ca3f97..d060020ba003382cd7bb9f95a2a40925c0e378b9 100644
--- a/pkg/kernel/lib/binary/ast_from_binary.dart
+++ b/pkg/kernel/lib/binary/ast_from_binary.dart
@@ -1067,8 +1067,10 @@ class BinaryBuilder {
         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());