Add warning and error markers to some tests

tests/language_strong/try_catch4_test.dart

Index: tests/language_strong/try_catch4_test.dart
diff --git a/tests/language_strong/try_catch4_test.dart b/tests/language_strong/try_catch4_test.dart
index 9d39f1173744a586b85b22b4df87848821f04544..c71b6d26bf7b3515444c619bd30e8e42f357c0ae 100644
--- a/tests/language_strong/try_catch4_test.dart
+++ b/tests/language_strong/try_catch4_test.dart
@@ -13,11 +13,11 @@ foo1() {
   var b = false;
   var entered = false;
   while (true) {
-    if (entered) return b;
+    if (entered) return b; /// static warning
     b = 8 == a; // This expression should not be GVN'ed.
     try {
       a = 8;
-      return;
+      return; /// static warning
     } finally {
       b = 8 == a;
       entered = true;
@@ -32,12 +32,12 @@ foo2() {
   var b = false;
   var entered = false;
   while (true) {
-    if (entered) return b;
+    if (entered) return b; /// static warning
     b = 8 == a; // This expression should not be GVN'ed.
     try {
       a = 8;
       doThrow();
-      return;
+      return; /// static warning
     } catch(e) {
       b = 8 == a;
       entered = true;
@@ -50,14 +50,14 @@ foo3() {
   var b = false;
   var entered = false;
   while (true) {
-    if (entered) return b;
+    if (entered) return b; /// static warning
     b = 8 == a; // This expression should not be GVN'ed.
     try {
       doThrow();
     } catch(e) {
       a = 8;
       entered = true;
-      return;
+      return; /// static warning
     } finally {
       b = 8 == a;
       entered = true;