Decreased nesting in threads test.

tests/threads.c

@@ -77,19 +77,17 @@ int main(void)
         exit(EXIT_FAILURE);
     }
 
-    if (thrd_create(&thread, thread_start, window) == thrd_success)
+    if (thrd_create(&thread, thread_start, window) != thrd_success)
     {
+        fprintf(stderr, "Failed to create secondary thread\n");
+        exit(EXIT_FAILURE);
+    }
+
     while (!glfwGetWindowParam(window, GLFW_CLOSE_REQUESTED))
         glfwWaitEvents();
 
     running = GL_FALSE;
     thrd_join(thread, &result);
-    }
-    else
-    {
-        fprintf(stderr, "Failed to create secondary thread\n");
-        exit(EXIT_FAILURE);
-    }
 
     exit(EXIT_SUCCESS);
 }