Format all tests.

tests/language/prefix7_negative_test.dart

Index: tests/language/prefix7_negative_test.dart
diff --git a/tests/language/prefix7_negative_test.dart b/tests/language/prefix7_negative_test.dart
index b098f657e684217bc5ec1453d8f5cbfc2892513e..21e313d8c4de3b1eecde4eee25993296a3b675c3 100644
--- a/tests/language/prefix7_negative_test.dart
+++ b/tests/language/prefix7_negative_test.dart
@@ -4,11 +4,11 @@
 //
 
 library Prefix7NegativeTest.dart;
+
 import "library10.dart" as lib10;
 
 // Top level variables cannot shadow library prefixes, they should collide.
 
 var lib10;
 
-main() {
-}
+main() {}