reduce the time cost for the testcase of test_nn_elementwise_grad (#26451)

python/paddle/fluid/tests/unittests/test_elementwise_nn_grad.py

@@ -29,7 +29,7 @@ class TestElementwiseMulDoubleGradCheck(unittest.TestCase):
     @prog_scope()
     def func(self, place):
         # the shape of input variable should be clearly specified, not inlcude -1.
-        shape = [2, 3, 7, 9]
+        shape = [2, 3, 4, 5]
         eps = 0.005
         dtype = np.float64
 
@@ -56,7 +56,7 @@ class TestElementwiseMulBroadcastDoubleGradCheck(unittest.TestCase):
     @prog_scope()
     def func(self, place):
         # the shape of input variable should be clearly specified, not inlcude -1.
-        shape = [2, 3, 7, 9]
+        shape = [2, 3, 4, 5]
         eps = 0.005
         dtype = np.float64
 
@@ -83,7 +83,7 @@ class TestElementwiseAddDoubleGradCheck(unittest.TestCase):
     @prog_scope()
     def func(self, place):
         # the shape of input variable should be clearly specified, not inlcude -1.
-        shape = [2, 3, 7, 9]
+        shape = [2, 3, 4, 5]
         eps = 0.005
         dtype = np.float64
 
@@ -110,7 +110,7 @@ class TestElementwiseAddBroadcastDoubleGradCheck(unittest.TestCase):
     @prog_scope()
     def func(self, place):
         # the shape of input variable should be clearly specified, not inlcude -1.
-        shape = [2, 3, 7, 9]
+        shape = [2, 3, 4, 5]
         eps = 0.005
         dtype = np.float64
 
@@ -137,7 +137,7 @@ class TestElementwiseSubDoubleGradCheck(unittest.TestCase):
     @prog_scope()
     def func(self, place):
         # the shape of input variable should be clearly specified, not inlcude -1.
-        shape = [2, 3, 7, 9]
+        shape = [2, 3, 4, 5]
         eps = 0.005
         dtype = np.float64
 
@@ -164,7 +164,7 @@ class TestElementwiseSubBroadcastDoubleGradCheck(unittest.TestCase):
     @prog_scope()
     def func(self, place):
         # the shape of input variable should be clearly specified, not inlcude -1.
-        shape = [2, 3, 7, 9]
+        shape = [2, 3, 4, 5]
         eps = 0.005
         dtype = np.float64
 
@@ -191,7 +191,7 @@ class TestElementwiseDivDoubleGradCheck(unittest.TestCase):
     @prog_scope()
     def func(self, place):
         # the shape of input variable should be clearly specified, not inlcude -1.
-        shape = [2, 3, 7, 9]
+        shape = [2, 3, 4, 5]
         eps = 0.0001
         dtype = np.float64
 
@@ -219,7 +219,7 @@ class TestElementwiseDivBroadcastDoubleGradCheck(unittest.TestCase):
     @prog_scope()
     def func(self, place):
         # the shape of input variable should be clearly specified, not inlcude -1.
-        shape = [2, 3, 7, 9]
+        shape = [2, 3, 4, 5]
         eps = 0.0001
         dtype = np.float64