Add ConstTensorsAsInput support for Conv3d

 * Constant weights and biases are now stored as Constant layers.
 * Updated Serializer, Deserializer and unit tests to reflect this.
 * Updated TfLiteParser.
 * Updated Ref backend to handle constant weights and
   bias as inputs rather than reading from member variables.
 * Added Conv3d EndToEnd test.
 * Added NCDHW DataLayout and unit tests.

Signed-off-by: Matthew Sloyan <matthew.sloyan@arm.com>
Change-Id: I10cdd354ca5f1c748730f92ffdb36bf810f83c8e
diff --git a/src/armnnSerializer/test/SerializerTestUtils.hpp b/src/armnnSerializer/test/SerializerTestUtils.hpp
index c6f148b..ce4d2cc 100644
--- a/src/armnnSerializer/test/SerializerTestUtils.hpp
+++ b/src/armnnSerializer/test/SerializerTestUtils.hpp
@@ -69,6 +69,7 @@
         {
             case armnn::LayerType::Input: break;
             case armnn::LayerType::Output: break;
+            case armnn::LayerType::Constant: break;
             default:
             {
                 VerifyNameAndConnections(layer, name);