Change a few more uses of the old try-catch syntax.

tests/language/try_catch3_test.dart

Index: tests/language/try_catch3_test.dart
diff --git a/tests/language/try_catch3_test.dart b/tests/language/try_catch3_test.dart
index d1701fd7f9bd1de0a4bfac50d992ef79ce4cfd36..804b38e4c63aa9f968a3c395eef55754aa26feaa 100644
--- a/tests/language/try_catch3_test.dart
+++ b/tests/language/try_catch3_test.dart
@@ -37,52 +37,52 @@ class Helper {
       try {
         int k = f2();
         f3();
-      } catch (MyException ex) {
+      } on MyException catch (ex) {
         int i = 10;
         print(i);
-      } catch (TestException ex) {
+      } on TestException catch (ex) {
         int k = 10;
         print(k);
       }
       try {
         j = j + 24;
-      } catch (var e) {
+      } catch (e) {
         i = 300;
         print(e.getMessage());
       }
       try {
         j += 20;
-      } catch (final e) {
+      } catch (e) {
         i = 400;
         print(e.getMessage());
       }
       try {
         j += 40;
-      } catch (var e) {
+      } catch (e) {
         i = 600;
         print(e.getMessage());
       }
       try {
         j += 60;
-      } catch (var e, var trace) {
+      } catch (e, trace) {
         i = 700;
         trace.printStackTrace(e);
         print(e.getMessage());
       }
       try {
         j += 80;
-      } catch (final MyException e) {
+      } on MyException catch (e) {
         i = 500;
         print(e.getMessage());
       }
-    } catch (MyParameterizedException<String, TestException> e, var trace) {
+    } on MyParameterizedException<String, TestException> catch (e, trace) {
       i = 800;
       trace.printStackTrace(e);
       throw;
-    } catch (MyException exception) {
+    } on MyException catch (exception) {
       i = 100;
       print(exception.getMessage());
-    } catch (TestException e, StackTrace trace) {
+    } on TestException catch (e, trace) {
       i = 200;
       trace.printStackTrace(e);
     } finally {