tests: kernel/msgq_api: add k_thread_join after k_thread_abort

On SMP systems, threads going through k_thread_abort() may still
be running while the test moves on to the next one. This creates
some interferences and may result in the next test failing. So
add k_thread_join() after k_thread_abort() to make sure those
threads have stopped before moving on.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>

tests/kernel/msgq/msgq_api/src/test_msgq_contexts.c

@@ -103,6 +103,8 @@ static void msgq_thread(struct k_msgq *pmsgq)
 
 	/**TESTPOINT: msgq purge*/
 	purge_msgq(pmsgq);
+
+	k_thread_join(tid, K_FOREVER);
 }
 
 static void thread_entry_overflow(void *p1, void *p2, void *p3)
@@ -145,6 +147,8 @@ static void msgq_thread_overflow(struct k_msgq *pmsgq)
 
 	/**TESTPOINT: msgq purge*/
 	k_msgq_purge(pmsgq);
+
+	k_thread_join(tid, K_FOREVER);
 }
 
 static void msgq_isr(struct k_msgq *pmsgq)
@@ -196,6 +200,9 @@ static void msgq_thread_data_passing(struct k_msgq *pmsgq)
 
 	/**TESTPOINT: msgq purge*/
 	k_msgq_purge(pmsgq);
+
+	k_thread_join(tid, K_FOREVER);
+	k_thread_join(tid1, K_FOREVER);
 }
 
 static void get_empty_entry(void *p1, void *p2, void *p3)
@@ -417,6 +424,7 @@ ZTEST(msgq_api_1cpu, test_msgq_empty)
 	zassert_equal(ret, 0);
 
 	k_thread_abort(tid);
+	k_thread_join(tid, K_FOREVER);
 }
 
 /**
@@ -449,6 +457,7 @@ ZTEST(msgq_api_1cpu, test_msgq_full)
 	/* that putting thread is being blocked now */
 	zassert_equal(tid->base.thread_state, _THREAD_PENDING);
 	k_thread_abort(tid);
+	k_thread_join(tid, K_FOREVER);
 }
 
 /**

tests/kernel/msgq/msgq_api/src/test_msgq_purge.c

@@ -44,6 +44,7 @@ static void purge_when_put(struct k_msgq *q)
 	}
 
 	k_thread_abort(&tdata);
+	k_thread_join(&tdata, K_FOREVER);
 }
 
 /**