refine the error of message test=develop (#27067)

python/paddle/fluid/layers/tensor.py

@@ -1446,6 +1446,8 @@ def linspace(start, stop, num, dtype=None, name=None):
     tensor_num = num
     tensor_start = start
     tensor_stop = stop
+    if not isinstance(num, Variable):
+        check_type(num, 'num', (int), 'linspace')
     if not isinstance(dtype, core.VarDesc.VarType):
         dtype = convert_np_dtype_to_dtype_(dtype)
     if not isinstance(start, Variable):
@@ -1471,8 +1473,6 @@ def linspace(start, stop, num, dtype=None, name=None):
         check_type(stop, 'stop', (int, float), 'linspace')
     if isinstance(num, Variable):
         check_dtype(num.dtype, 'num', ['int32'], 'linspace')
-    else:
-        check_type(num, 'num', (int), 'linspace')
     check_dtype(dtype, 'dtype', ['int32', 'int64', 'float32', 'float64'],
                 'linspace')