Update corelib/ and lib/ to use the new try-catch syntax.

lib/dom/scripts/idlparser_test.dart

Index: lib/dom/scripts/idlparser_test.dart
diff --git a/lib/dom/scripts/idlparser_test.dart b/lib/dom/scripts/idlparser_test.dart
index 3ef11f33adec043b87f8dc4419ecef8ba6e572d0..bfe29065b79038c533ca54c2e86cf8e606a3382c 100644
--- a/lib/dom/scripts/idlparser_test.dart
+++ b/lib/dom/scripts/idlparser_test.dart
@@ -68,7 +68,7 @@ show(grammar, rule, input) {
   var ast;
   try {
     ast = grammar.parse(rule, input);
-  } catch (var exception) {
+  } catch (exception) {
     if (exception is ParseError)
       ast = exception;
     else
@@ -85,7 +85,7 @@ void check(grammar, rule, input, expected) {
   var ast;
   try {
     ast = grammar.parse(rule, input);
-  } catch (var exception) {
+  } catch (exception) {
     ast = exception;
   }