Implement nested switches and missing switch continue targets.

pkg/front_end/lib/src/fasta/testing/kernel_chain.dart

Index: pkg/front_end/lib/src/fasta/testing/kernel_chain.dart
diff --git a/pkg/front_end/lib/src/fasta/testing/kernel_chain.dart b/pkg/front_end/lib/src/fasta/testing/kernel_chain.dart
index 638b5761667c6e3285777136f017264bd283eae1..0a714a830b673718d0e79aa5ea954632281a83c1 100644
--- a/pkg/front_end/lib/src/fasta/testing/kernel_chain.dart
+++ b/pkg/front_end/lib/src/fasta/testing/kernel_chain.dart
@@ -192,12 +192,12 @@ class Verify extends Step<Program, Program, TestContext> {
   String get name => "verify";
 
   Future<Result<Program>> run(Program program, TestContext testContext) async {
-    try {
-      verifyProgram(program, isOutline: !fullCompile);
+    var errors = verifyProgram(program, isOutline: !fullCompile);
+    if (errors.isEmpty) {
       return pass(program);
-    } catch (e, s) {
+    } else {
       return new Result<Program>(
-          null, testContext.expectationSet["VerificationError"], e, s);
+          null, testContext.expectationSet["VerificationError"], errors, null);
     }
   }
 }