Get rid of 'close' on process. It is very easy to use incorrectly and cut off data from your stream…

tests/standalone/io/process_exit_test.dart

Index: tests/standalone/io/process_exit_test.dart
diff --git a/tests/standalone/io/process_exit_test.dart b/tests/standalone/io/process_exit_test.dart
index 84e5865db8a4a4d2ab02a65d15a42ccb0cedc070..a745bfed65910744c3f348041c7501468285e02b 100644
--- a/tests/standalone/io/process_exit_test.dart
+++ b/tests/standalone/io/process_exit_test.dart
@@ -14,8 +14,9 @@ testExit() {
   future.then((process) {
     process.onExit = (int exitCode) {
       Expect.equals(exitCode, 99);
-      process.close();
     };
+    process.stdout.onData = process.stdout.read;
+    process.stderr.onData = process.stderr.read;
   });
 }