Implement nested switches and missing switch continue targets.

pkg/front_end/lib/src/fasta/kernel/verifier.dart

Index: pkg/front_end/lib/src/fasta/kernel/verifier.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/verifier.dart b/pkg/front_end/lib/src/fasta/kernel/verifier.dart
index e95cfe69f0dbd71279f1644ab9431913be561f60..57114240103d75efc51f2b8cca5dfb1fce79f612 100644
--- a/pkg/front_end/lib/src/fasta/kernel/verifier.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/verifier.dart
@@ -23,12 +23,11 @@ import '../errors.dart' show printUnexpected;
 
 import 'redirecting_factory_body.dart' show RedirectingFactoryBody;
 
-void verifyProgram(Program program, {bool isOutline: false}) {
+List<VerificationError> verifyProgram(Program program,
+    {bool isOutline: false}) {
   FastaVerifyingVisitor verifier = new FastaVerifyingVisitor(isOutline);
   program.accept(verifier);
-  if (verifier.errors.isNotEmpty) {
-    throw verifier.errors.first;
-  }
+  return verifier.errors;
 }
 
 class FastaVerifyingVisitor extends VerifyingVisitor {