Fix linker error: replace zval_dtor with zval_ptr_dtor

Replace all occurrences of zval_dtor(&options) with zval_ptr_dtor(&options)
in async_API.c and scheduler.c. The function zval_dtor does not exist in
the ZEND_API; the correct function is zval_ptr_dtor which is exported.

This fixes:
- async_API.obj : error LNK2001: unresolved external symbol zval_dtor
- scheduler.obj : error LNK2001: unresolved external symbol zval_dtor

Author: EdmondDantes

async_API.c

@@ -109,11 +109,11 @@ zend_coroutine_t *spawn(zend_async_scope_t *scope, zend_object *scope_provider,
 	zval options;
 	ZVAL_UNDEF(&options);
 	if (!scope->before_coroutine_enqueue(&coroutine->coroutine, scope, &options)) {
-		zval_dtor(&options);
+		zval_ptr_dtor(&options);
 		coroutine->coroutine.event.dispose(&coroutine->coroutine.event);
 		return NULL;
 	}
-	zval_dtor(&options);
+	zval_ptr_dtor(&options);
 
 	const bool is_spawn_strategy =
 			scope_provider != NULL && instanceof_function(scope_provider->ce, async_ce_spawn_strategy);
@@ -136,7 +136,7 @@ zend_coroutine_t *spawn(zend_async_scope_t *scope, zend_object *scope_provider,
 			return NULL;
 		}
 
-		zval_dtor(&options);
+		zval_ptr_dtor(&options);
 	}
 
 	zend_async_waker_t *waker = zend_async_waker_new(&coroutine->coroutine);
@@ -187,7 +187,7 @@ zend_coroutine_t *spawn(zend_async_scope_t *scope, zend_object *scope_provider,
 			return NULL;
 		}
 
-		zval_dtor(&options);
+		zval_ptr_dtor(&options);
 	}
 
 	if (UNEXPECTED(zend_hash_index_add_ptr(&ASYNC_G(coroutines), coroutine->std.handle, coroutine) == NULL)) {

scheduler.c

@@ -801,10 +801,10 @@ bool async_scheduler_launch(void)
 	zval options;
 	ZVAL_UNDEF(&options);
 	if (!scope->before_coroutine_enqueue(&main_coroutine->coroutine, scope, &options)) {
-		zval_dtor(&options);
+		zval_ptr_dtor(&options);
 		return false;
 	}
-	zval_dtor(&options);
+	zval_ptr_dtor(&options);
 
 	scope->after_coroutine_enqueue(&main_coroutine->coroutine, scope);
 	if (UNEXPECTED(EG(exception) != NULL)) {
@@ -878,10 +878,10 @@ bool async_scheduler_launch(void)
 
 	ZVAL_UNDEF(&options);
 	if (!scope->before_coroutine_enqueue(scheduler_coroutine, scope, &options)) {
-		zval_dtor(&options);
+		zval_ptr_dtor(&options);
 		return false;
 	}
-	zval_dtor(&options);
+	zval_ptr_dtor(&options);
 
 	scope->after_coroutine_enqueue(scheduler_coroutine, scope);
 	if (UNEXPECTED(EG(exception) != NULL)) {