IVGCVSW-7735 Opaque Delegate Cleanup

 * Move TFL_TheStableDelegate to opaque/armnn_delegate_external.cpp
 * Change TFL_TheStableDelegate to extern variable
 * Remove duplicated opaque test sources
 * Add support for missing Fill operator
 * Enable support for Mirror Pad
 * Fix failing Split tests

Signed-off-by: Ryan OShea <ryan.oshea3@arm.com>
Signed-off-by: Matthew Sloyan <matthew.sloyan@arm.com>
Change-Id: I7f8d8b4269bb4fbe27b6f47709cbd828554d37d8
diff --git a/delegate/opaque/include/armnn_delegate.hpp b/delegate/opaque/include/armnn_delegate.hpp
index bb6451f..ff860c4 100644
--- a/delegate/opaque/include/armnn_delegate.hpp
+++ b/delegate/opaque/include/armnn_delegate.hpp
@@ -6,6 +6,7 @@
 #pragma once
 
 #include <DelegateOptions.hpp>
+#include <Version.hpp>
 
 #include <tensorflow/core/public/version.h>
 #include <tensorflow/lite/c/c_api_opaque.h>
@@ -86,8 +87,6 @@
 /// In order for the delegate to be loaded by TfLite
 const TfLiteOpaqueDelegatePlugin* GetArmnnDelegatePluginApi();
 
-extern const TfLiteStableDelegate TFL_TheStableDelegate;
-
 using tflite::delegates::DelegatePluginInterface;
 using TfLiteOpaqueDelegatePtr = tflite::delegates::TfLiteDelegatePtr;