Fix process test and implementation after change to setter for registering event handler.

tests/standalone/src/ProcessExitNegativeTest.dart

Index: tests/standalone/src/ProcessExitNegativeTest.dart
diff --git a/tests/standalone/src/ProcessExitNegativeTest.dart b/tests/standalone/src/ProcessExitNegativeTest.dart
index dceead4178ee44b0036609bb9870bc1808b2aa82..2209f82832447717dd56d8fdaf64d00846922189 100644
--- a/tests/standalone/src/ProcessExitNegativeTest.dart
+++ b/tests/standalone/src/ProcessExitNegativeTest.dart
@@ -7,11 +7,9 @@
 
 void main() {
   Process p = new Process("true", []);
-  p.setExitHandler(
-    (int s) {
-      print(a.toString());  // Should cause a compilation error here.
-      p.close();
-    }
-  );
+  p.exitHandler = (int s) {
+    print(a.toString());  // Should cause a compilation error here.
+    p.close();
+  };
   p.start();
 }