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

lib/compiler/implementation/compiler.dart

Index: lib/compiler/implementation/compiler.dart
diff --git a/lib/compiler/implementation/compiler.dart b/lib/compiler/implementation/compiler.dart
index 9b7dc28194c3193ab3ca9bdb991b09d6b47a696c..ec4a5cb689c822771329656a1cda72d3550233f3 100644
--- a/lib/compiler/implementation/compiler.dart
+++ b/lib/compiler/implementation/compiler.dart
@@ -110,16 +110,16 @@ class Compiler implements DiagnosticListener {
     _currentElement = element;
     try {
       return f();
-    } catch (CompilerCancelledException ex) {
+    } on CompilerCancelledException catch (ex) {
       throw;
-    } catch (StackOverflowException ex) {
+    } on StackOverflowException catch (ex) {
       // We cannot report anything useful in this case, because we
       // do not have enough stack space.
       throw;
-    } catch (var ex) {
+    } catch (ex) {
       try {
         unhandledExceptionOnElement(element);
-      } catch (var doubleFault) {
+      } catch (doubleFault) {
         // Ignoring exceptions in exception handling.
       }
       throw;
@@ -264,7 +264,7 @@ class Compiler implements DiagnosticListener {
   bool run(Uri uri) {
     try {
       runCompiler(uri);
-    } catch (CompilerCancelledException exception) {
+    } on CompilerCancelledException catch (exception) {
       log(exception.toString());
       log('compilation failed');
       return false;