[Dy2stat] Disable PaddleInference IR Optimization in test_mnist for CUDA11 (#29105)

test_mnist failed on CUDA11. We found that it is due to PaddleInference IR Optimization after debugging. We disable it in this PR and we will re-enable it after PaddleInference fixes it.

python/paddle/fluid/tests/unittests/dygraph_to_static/CMakeLists.txt

 file(GLOB TEST_OPS RELATIVE "${CMAKE_CURRENT_SOURCE_DIR}" "test_*.py")
 string(REPLACE ".py" "" TEST_OPS "${TEST_OPS}")
 
-# disable for cuda11
-list(REMOVE_ITEM TEST_OPS test_mnist)
-list(REMOVE_ITEM TEST_OPS test_resnet)
-
 foreach(TEST_OP ${TEST_OPS})
     py_test_modules(${TEST_OP} MODULES ${TEST_OP})
 endforeach(TEST_OP)

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

@@ -57,7 +57,9 @@ class PredictorTools(object):
         config.switch_use_feed_fetch_ops(False)
         config.enable_memory_optim()
         config.disable_glog_info()
-        config.switch_ir_optim(True)
+        # TODO: set it to True after PaddleInference fix the precision error
+        # in CUDA11
+        config.switch_ir_optim(False)
 
         return config