Fix VPrintHelper used on Windows.

src/platform-win32.cc

Index: src/platform-win32.cc
diff --git a/src/platform-win32.cc b/src/platform-win32.cc
index 56261735b871ee2166498f877ced615baf4efa7f..930795602a9ac7e313598754dbf2f8061f7e0e41 100644
--- a/src/platform-win32.cc
+++ b/src/platform-win32.cc
@@ -662,15 +662,15 @@ static bool HasConsole() {
 
 
 static void VPrintHelper(FILE* stream, const char* format, va_list args) {
-  if (HasConsole()) {
-    vfprintf(stream, format, args);
-  } else {
+  if ((stream == stdout || stream == stderr) && !HasConsole()) {
     // It is important to use safe print here in order to avoid
     // overflowing the buffer. We might truncate the output, but this
     // does not crash.
     EmbeddedVector<char, 4096> buffer;
     OS::VSNPrintF(buffer, format, args);
     OutputDebugStringA(buffer.start());
+  } else {
+    vfprintf(stream, format, args);
   }
 }