IVGCVSW-4386 Add ArmNN reference support for QAsymmS8

 * Added Quantization Scheme for QAsymmS8
 * Added Unit Tests for QAsymmS8
 * Renamed QAsymm8 calls to QAsymmU8

Signed-off-by: Ryan OShea <Ryan.OShea2@arm.com>
Change-Id: I897b4e018ba1d808cc3f8c113f2be2dbad49c8db
diff --git a/src/backends/reference/RefLayerSupport.cpp b/src/backends/reference/RefLayerSupport.cpp
index 0ca19bb..c60348e 100644
--- a/src/backends/reference/RefLayerSupport.cpp
+++ b/src/backends/reference/RefLayerSupport.cpp
@@ -610,7 +610,8 @@
 {
    bool supported = true;
 
-    std::array<DataType,3> supportedInputTypes = {
+    std::array<DataType,4> supportedInputTypes = {
+        DataType::QAsymmS8,
         DataType::QAsymmU8,
         DataType::QSymmS8,
         DataType::QSymmS16
@@ -1439,9 +1440,10 @@
    bool supported = true;
 
     // Define supported input types.
-    std::array<DataType,5> supportedInputTypes = {
+    std::array<DataType,6> supportedInputTypes = {
         DataType::Float32,
         DataType::Float16,
+        DataType::QAsymmS8,
         DataType::QAsymmU8,
         DataType::QSymmS8,
         DataType::QSymmS16
@@ -1451,8 +1453,9 @@
                                   "Reference quantize: input type not supported.");
 
     // Define supported output types.
-    std::array<DataType,3> supportedOutputTypes = {
+    std::array<DataType,4> supportedOutputTypes = {
         DataType::QAsymmU8,
+        DataType::QAsymmS8,
         DataType::QSymmS8,
         DataType::QSymmS16
     };