IVGCVSW-2925: Combine Pad with Convolution2d in the Optimizer

* Added new optimization for folding pad layer into convolution2d layer following it
* Added new test in OptimizerTests.cpp
* Added new optimization into All optimizations
* Added call to new optimization in Optimize in Network.cpp
* Updated CMakeLists.txt

Signed-off-by: Nina Drozd <nina.drozd@arm.com>
Change-Id: I682e07c71bbd42c49c02dda30a848a9ab2b16e7e
diff --git a/src/armnn/Network.cpp b/src/armnn/Network.cpp
index c1462c0..0bd8d4b 100644
--- a/src/armnn/Network.cpp
+++ b/src/armnn/Network.cpp
@@ -436,7 +436,8 @@
                                                 OptimizeInversePermutes(),
                                                 MovePermuteUp(),
                                                 PermuteAsReshape(),
-                                                OptimizeConsecutiveReshapes()));
+                                                OptimizeConsecutiveReshapes(),
+                                                FoldPadIntoConvolution2d()));
 
     // Infer the tensor infos for all output slots. Throws an exception on failure
     optGraph.InferTensorInfos();