reduce the execution time of affine_channel op unittests (#26393)

* reduce the execution time of affine_channel op unittests

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

@@ -63,7 +63,7 @@ class TestAffineChannelOp(OpTest):
         self.check_grad(['X'], 'Out', no_grad_set=set(['Scale', 'Bias']))
 
     def init_test_case(self):
-        self.shape = [2, 100, 12, 12]
+        self.shape = [2, 100, 3, 3]
         self.C = 100
         self.layout = 'NCHW'
 
@@ -102,7 +102,7 @@ class TestAffineChannelOpError(unittest.TestCase):
 
 class TestAffineChannelNHWC(TestAffineChannelOp):
     def init_test_case(self):
-        self.shape = [2, 12, 12, 100]
+        self.shape = [2, 3, 3, 100]
         self.C = 100
         self.layout = 'NHWC'
 
@@ -115,7 +115,7 @@ class TestAffineChannelNHWC(TestAffineChannelOp):
 
 class TestAffineChannel2D(TestAffineChannelOp):
     def init_test_case(self):
-        self.shape = [8, 100]
+        self.shape = [2, 100]
         self.C = 100
         self.layout = 'NCHW'