Followup to https://codereview.chromium.org/1001673002/

util/test/thread_win.cc

Index: util/test/thread_win.cc
diff --git a/util/test/thread_win.cc b/util/test/thread_win.cc
index 797d9c23ccdfa438b4b512373a16e059bf0c5d67..1e277ebd7b1c51a6731a9fc2c2e6f87ddce04b30 100644
--- a/util/test/thread_win.cc
+++ b/util/test/thread_win.cc
@@ -28,7 +28,7 @@ void Thread::Start() {
 }
 
 void Thread::Join() {
-  ASSERT_FALSE(platform_thread_);
+  ASSERT_TRUE(platform_thread_);
   DWORD result = WaitForSingleObject(platform_thread_, INFINITE);
   EXPECT_EQ(WAIT_OBJECT_0, result) << ErrorMessage("WaitForSingleObject");
   platform_thread_ = 0;