[MO] IR Reader updates for support IR generated by PDPD FE (#7646)

* Add extender for LSTMSequence operation

* Update BOM file

* Update gather shape inference function to support 1D tensors as axis

* Refactor split_normalize_output function usage

* Update temporary Result operations processing

* Revert fake split output renaming

* Revert kaldi assign result removing

* Add assert for node type

* Update model-optimizer/mo/utils/ir_reader/layer_to_class.py

Fix comment

Co-authored-by: Evgenya Stepyreva <evgenya.stepyreva@intel.com>

* Update model-optimizer/extensions/ops/gather.py

Update axis value check.

Co-authored-by: Evgenya Stepyreva <evgenya.stepyreva@intel.com>

Co-authored-by: Evgenya Stepyreva <evgenya.stepyreva@intel.com>

model-optimizer/automation/package_BOM.txt

@@ -1049,6 +1049,7 @@ mo/utils/ir_reader/extenders/if_extender.py
 mo/utils/ir_reader/extenders/interpolate_extender.py
 mo/utils/ir_reader/extenders/loop_extender.py
 mo/utils/ir_reader/extenders/LSTMCell_extender.py
+mo/utils/ir_reader/extenders/LSTMSequence_extender.py
 mo/utils/ir_reader/extenders/non_max_suppression_extender.py
 mo/utils/ir_reader/extenders/non_zero_extender.py
 mo/utils/ir_reader/extenders/pad_extender.py

model-optimizer/extensions/ops/gather.py

@@ -52,6 +52,10 @@ class Gather(Op):
         indices_shape = node.in_port(1).data.get_shape()
         assert indices_shape is not None
         axis = node.in_port(2).data.get_value()
+
+        # axis of Gather could be accepted as both scalar and 1D tensor
+        if isinstance(axis, np.ndarray):
+            axis = axis.item()
         assert axis is not None, 'axis input is undefined'
 
         assert -len(data_shape) <= axis < len(data_shape), \

model-optimizer/mo/utils/ir_reader/extenders/LSTMSequence_extender.py

@@ -0,0 +1,13 @@
+# Copyright (C) 2018-2021 Intel Corporation
+# SPDX-License-Identifier: Apache-2.0
+
+from mo.utils.graph import Node
+from mo.utils.ir_reader.extender import Extender
+
+
+class LSTMSequence_extender(Extender):
+    op = 'LSTMSequence'
+
+    @staticmethod
+    def extend(op: Node):
+        op['infer'] = Extender.use_shapes_from_ir

model-optimizer/mo/utils/ir_reader/layer_to_class.py

@@ -345,6 +345,8 @@ def copy_graph_with_ops(graph: Graph) -> Graph:
                 log.warning('Operation {} is not found in MO operations, please check it! '
                             'Simple shape infer function is used'.format(op_type))
                 node = Op(new_graph, op.attrs()).create_node()
+                assert 'type' in node, 'Operation {} have no `type` attribute.'.format(node.soft_get('name'))
+                node['op'] = node.type
                 node['infer'] = Extender.use_shapes_from_ir
                 if 'ir_data_attrs' in op:
                     node['IE'] = [('layer',