Re-land "Format all multitests"

tests/language/duplicate_interface_negative_test.dart

Index: tests/language/duplicate_interface_negative_test.dart
diff --git a/tests/language/duplicate_interface_negative_test.dart b/tests/language/duplicate_interface_negative_test.dart
index c7e9f855a4e6ac147325c1670877525f43336dc0..b83a8fdd8c6bbd12067f5c240d5c081490007426 100644
--- a/tests/language/duplicate_interface_negative_test.dart
+++ b/tests/language/duplicate_interface_negative_test.dart
@@ -8,13 +8,10 @@ library duplicateInterfaceNegativeTest;
 import "duplicate_interface_lib.dart" as alib;
 import "duplicate_interface_lib.dart" show InterfA;
 
-
 // Expect error since InterfA and alib.InterfA refer to the same interface.
 class Foo implements InterfA, alib.InterfA { } //# compile-time error
 
-
 main() {
   Expect.isTrue(new Foo() is InterfA);
   Expect.isTrue(new Foo() is alib.InterfA);
 }
-