Correct stack base calculation on Mac and NuttX

VELAPLATFO-1343

Signed-off-by: Huang Qi <huangqi3@xiaomi.com>
Change-Id: I3b69cd1c4819e494f16e32582c6764bcfb0075fe

Author: no1wudi

core/shared/platform/common/posix/posix_thread.c

@@ -327,8 +327,10 @@ os_thread_get_stack_boundary()
     if ((addr = (uint8 *)pthread_get_stackaddr_np(self))) {
         stack_size = pthread_get_stacksize_np(self);
         if (stack_size > max_stack_size)
-            addr -= max_stack_size;
-        else
+            stack_size = max_stack_size;
+
+        /* Check whether stack_addr is the base or end of the stack */
+        if (addr > (uint8 *)&stack_size)
             addr -= stack_size;
         /* Reserved 1 guard page at least for safety */
         addr += page_size;