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

tests/standalone/io/file_fuzz_test.dart

Index: tests/standalone/io/file_fuzz_test.dart
diff --git a/tests/standalone/io/file_fuzz_test.dart b/tests/standalone/io/file_fuzz_test.dart
index abb6fc0f70af5bb233093178d11d4f5a73fded10..313575ea6e55aa47ddd1b33832f47f2ef4460511 100644
--- a/tests/standalone/io/file_fuzz_test.dart
+++ b/tests/standalone/io/file_fuzz_test.dart
@@ -5,10 +5,10 @@
 // 'fuzz' test the file APIs by providing unexpected type arguments. The test
 // passes if the VM does not crash.
 
-#import('dart:io');
-#import('dart:isolate');
+import "dart:io";
+import "dart:isolate";
 
-#import('fuzz_support.dart');
+import "fuzz_support.dart";
 
 fuzzSyncMethods() {
   typeMapping.forEach((k, v) {