Flatten input_spec when check neg shape (#50692)

* Flatten input_spec when check neg shape

* Fix cycle import

python/paddle/jit/dy2static/program_translator.py

@@ -19,6 +19,7 @@ import threading
 import warnings
 import weakref
 
+import paddle
 from paddle.fluid import _non_static_mode, core, framework
 from paddle.fluid.data_feeder import check_type
 from paddle.fluid.dygraph import layers
@@ -324,8 +325,11 @@ class StaticFunction:
         if input_spec is not None and prim_or_cinn_is_enabled(
             kwargs.get("build_strategy", None)
         ):
-            for spec in input_spec:
-                if spec is not None and -1 in spec.shape:
+            for spec in flatten(input_spec):
+                if (
+                    isinstance(spec, paddle.static.InputSpec)
+                    and -1 in spec.shape
+                ):
                     input_spec = None
                     warnings.warn(
                         'Now prim and cinn do not support -1 shape, but input_spec has -1 shape so we set it to None.'