fix:tencentos:memory leak issue in platform_thread_destroy

In tencentos implementation of platform_thread_destroy, stack size is
getting freed where as stack base is suppose to be freed.

platform_thread_t structure varaible is also not freed. this patch fix
both the issues

Signed-off-by: Ajay Bhargav <ajay.bhargav@waybyte.in>

Author: ajaybhargav

platform/TencentOS-tiny/platform_thread.c

@@ -59,8 +59,8 @@ void platform_thread_destroy(platform_thread_t* thread)
 {
     if (NULL != thread)
         tos_task_destroy(&(thread->thread));
+    platform_memory_free(thread->thread.stk_base);
     platform_memory_free(&(thread->thread));
-    platform_memory_free(&(thread->thread.stk_size));
 }