Add stacktrace_test

tests/compiler/dart2js/sourcemaps/diff_view.dart

Index: tests/compiler/dart2js/sourcemaps/diff_view.dart
diff --git a/tests/compiler/dart2js/sourcemaps/diff_view.dart b/tests/compiler/dart2js/sourcemaps/diff_view.dart
index bd29b49f3b3731f042e59b27bb85c17381cff10f..db07f93c0619af5e65993911c3b1353c0722b36b 100644
--- a/tests/compiler/dart2js/sourcemaps/diff_view.dart
+++ b/tests/compiler/dart2js/sourcemaps/diff_view.dart
@@ -69,9 +69,8 @@ main(List<String> args) async {
     // deleted.
     // Use default options; comparing SSA and CPS output using the new
     // source information strategy.
+    options.add(commonArguments);
     options.add([Flags.useNewSourceInfo]..addAll(commonArguments));
-    options.add([Flags.useNewSourceInfo]..addAll(commonArguments));
-    throw "missing options: please specify options for the second column";
   } else if (optionSegments.length == 2) {
     // Use alternative options for the second output column.
     options.add(commonArguments);
@@ -793,7 +792,7 @@ Future<CodeLinesResult> computeCodeLines(
     if (!added) {
       int offset;
       if (options.contains(Flags.useNewSourceInfo)) {
-        offset = step.offset.subexpressionOffset;
+        offset = step.offset.value;
       } else {
         offset = info.jsCodePositions[step.node].startPosition;
       }