Revert comment change

Author: kleisauke

tests/pthread/main_thread_join.cpp

@@ -32,8 +32,8 @@ void loop() {
 
 void *ThreadMain(void *arg) {
 #ifdef TRY_JOIN
-  // Delay to force the main thread to try and succeed a few times before
-  // canceling the main loop.
+  // Delay to force the main thread to try and fail a few times before
+  // succeeding.
   while (tries.load() < EXPECTED_TRIES) {}
 #else
   // Delay a bit to force the main thread to actually block, as exited