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

tests/lib/math/math_test.dart

Index: tests/lib/math/math_test.dart
diff --git a/tests/lib/math/math_test.dart b/tests/lib/math/math_test.dart
index 2481ec7786c2ed64a07e53db5e8c70fb6c9847ed..d56fbaf764a461744fa9ee6708bbd9c0b3ebbea0 100644
--- a/tests/lib/math/math_test.dart
+++ b/tests/lib/math/math_test.dart
@@ -155,7 +155,7 @@ class MathTest {
     try {
       parseInt(str);
       return false;
-    } catch (FormatException e) {
+    } on FormatException catch (e) {
       return true;
     }
   }