Remove old #import, #source, and #library syntax from tests/standalone.

tests/standalone/io/echo_server_test.dart

Index: tests/standalone/io/echo_server_test.dart
diff --git a/tests/standalone/io/echo_server_test.dart b/tests/standalone/io/echo_server_test.dart
index c002971c3878092dc983a2c6825bef62794d6a79..27c31282960bf610beec5b87a7d89be20cc90202 100644
--- a/tests/standalone/io/echo_server_test.dart
+++ b/tests/standalone/io/echo_server_test.dart
@@ -9,10 +9,10 @@
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
 
-#library("EchoServerTest.dart");
-#import("dart:io");
-#import("dart:isolate");
-#source("testing_server.dart");
+library ServerTest;
+import "dart:io";
+import "dart:isolate";
+part "testing_server.dart";
 
 class EchoServerTest {