fix uniform_random op,test=develop (#17492)

python/paddle/fluid/layers/ops.py

@@ -86,9 +86,9 @@ def uniform_random(shape, dtype='float32', min=-1.0, max=1.0, seed=0):
             result = fluid.layers.uniform_random(shape=[32, 784])
     """
 
-    locals_var = locals()
     if not isinstance(dtype, core.VarDesc.VarType):
         dtype = convert_np_dtype_to_dtype_(dtype)
+    locals_var = locals()
     kwargs = dict()
     for name, val in locals_var.items():
         if val is not None: