Update almost all tests (except co19) to use the new try-catch syntax.

tests/compiler/dart2js_foreign/native_null_closure_test.dart

Index: tests/compiler/dart2js_foreign/native_null_closure_test.dart
diff --git a/tests/compiler/dart2js_foreign/native_null_closure_test.dart b/tests/compiler/dart2js_foreign/native_null_closure_test.dart
index f916a1211fc3bcc04c002330783bee2e0a5a0828..8f7aa203ff64948948e2822f3a5ad37cf009949f 100644
--- a/tests/compiler/dart2js_foreign/native_null_closure_test.dart
+++ b/tests/compiler/dart2js_foreign/native_null_closure_test.dart
@@ -31,7 +31,7 @@ main() {
   bool caughtException = false;
   try {
     a.invoke();
-  } catch (Exception e) {
+  } on Exception catch (e) {
     caughtException = true;
   }
   Expect.isTrue(caughtException);