Revert "tests/kernel/threads: Augment abort_from_isr test to detect FMW"

This reverts commit 3ef282b.

This PR introduced 2 regressions in main CI:
71977 & 71978
Let's revert it by now to get main's CI passing again.

Signed-off-by: Alberto Escolar Piedras <[email protected]>

Author: aescolar

tests/kernel/threads/thread_apis/src/test_threads_cancel_abort.c

@@ -166,11 +166,6 @@ static void offload_func(const void *param)
 
 	k_thread_abort(t);
 
-	/* Thread memory is unused now, validate that we can clobber it. */
-	if (!IS_ENABLED(CONFIG_ARCH_POSIX)) {
-		memset(t, 0, sizeof(*t));
-	}
-
 	/* k_thread_abort() in an isr shouldn't affect the ISR's execution */
 	isr_finished = true;
 }
@@ -206,19 +201,6 @@ ZTEST(threads_lifecycle, test_abort_from_isr)
 	k_thread_join(&tdata, K_FOREVER);
 	zassert_true(isr_finished, "ISR did not complete");
 
-	/* Thread struct was cleared after the abort, make sure it is
-	 * still clear (i.e. that the arch layer didn't write to it
-	 * during interrupt exit).  Doesn't work on posix, which needs
-	 * the thread struct for its swap code.
-	 */
-	uint8_t *p = (uint8_t *)&tdata;
-
-	if (!IS_ENABLED(CONFIG_ARCH_POSIX)) {
-		for (int i = 0; i < sizeof(tdata); i++) {
-			zassert_true(p[i] == 0, "Free memory write to aborted thread");
-		}
-	}
-
 	/* Notice: Recover back the offload_sem: This is use for releasing
 	 * offload_sem which might be held when thread aborts itself in ISR
 	 * context, it will cause irq_offload cannot be used again.
@@ -266,5 +248,6 @@ ZTEST(threads_lifecycle, test_abort_from_isr_not_self)
 	/* Simulate taking an interrupt which kills spwan thread */
 	irq_offload(offload_func, (void *)tid);
 
+	k_thread_join(&tdata, K_FOREVER);
 	zassert_true(isr_finished, "ISR did not complete");
 }