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

tests/language/named_parameters4_negative_test.dart

Index: tests/language/named_parameters4_negative_test.dart
diff --git a/tests/language/named_parameters4_negative_test.dart b/tests/language/named_parameters4_negative_test.dart
index 719d754fee2d91d56b1c7da6ac284438a4095cc6..cdd5c0ada8d1dcc1783a1b2e3c7da0ca660fec38 100644
--- a/tests/language/named_parameters4_negative_test.dart
+++ b/tests/language/named_parameters4_negative_test.dart
@@ -13,7 +13,7 @@ class NamedParameters4NegativeTest {
   static testMain() {
     try {
       F31(10, b:25, b:35);  // Duplicate named argument.
-    } catch (var e) {
+    } catch (e) {
       // This is a negative test that should not compile.
       // If it runs due to a bug, catch and ignore exceptions.
     }