Switch some dy2st UT to eager (#41175)

python/paddle/fluid/tests/unittests/dygraph_to_static/test_cycle_gan.py

@@ -631,4 +631,5 @@ class TestCycleGANModel(unittest.TestCase):
 
 
 if __name__ == "__main__":
-    unittest.main()
+    with fluid.framework._test_eager_guard():
+        unittest.main()

python/paddle/fluid/tests/unittests/dygraph_to_static/test_lac.py

@@ -610,4 +610,5 @@ class TestLACModel(unittest.TestCase):
 
 
 if __name__ == "__main__":
-    unittest.main()
+    with fluid.framework._test_eager_guard():
+        unittest.main()

python/paddle/fluid/tests/unittests/dygraph_to_static/test_resnet_amp.py

@@ -116,4 +116,5 @@ class TestResnet(unittest.TestCase):
 
 
 if __name__ == '__main__':
-    unittest.main()
+    with fluid.framework._test_eager_guard():
+        unittest.main()

python/paddle/fluid/tests/unittests/dygraph_to_static/test_resnet_pure_fp16.py

@@ -125,4 +125,5 @@ class TestResnet(unittest.TestCase):
 
 
 if __name__ == '__main__':
-    unittest.main()
+    with fluid.framework._test_eager_guard():
+        unittest.main()