Fix ODR violation that can break WTF::String pretty printing in tests.

Source/wtf/testing/WTFTestPrinters.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 11 matching lines @@
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
-#include "wtf/testing/WTFTestHelpers.h"
 
 #include "wtf/text/WTFString.h"
-#include <ios> // NOLINT
 #include <ostream> // NOLINT
 
 namespace WTF {
 
 std::ostream& operator<<(std::ostream& out, const String& string)
 {
     if (string.isNull())
         return out << "<null>";
 
     out << '"';
@@ skipping 28 matching lines @@
                 out.setf(std::ios::uppercase);
                 out << character;
             }
             break;
         }
     }
     return out << '"';
 }
 
 } // namespace WTF