IVGCVSW-4211 Add Signed 8 bit Quantisation support into the Reference backend

!android-nn-driver:2435

Signed-off-by: Finn Williams <Finn.Williams@arm.com>
Change-Id: I10ecd4a8937725953396805f33a3562a5384c4d4
diff --git a/src/backends/backendsCommon/test/layerTests/QuantizeTestImpl.hpp b/src/backends/backendsCommon/test/layerTests/QuantizeTestImpl.hpp
index a2e1a49..ece75fd 100644
--- a/src/backends/backendsCommon/test/layerTests/QuantizeTestImpl.hpp
+++ b/src/backends/backendsCommon/test/layerTests/QuantizeTestImpl.hpp
@@ -18,6 +18,10 @@
     armnn::IWorkloadFactory& workloadFactory,
     const armnn::IBackendInternal::IMemoryManagerSharedPtr& memoryManager);
 
+LayerTestResult<int8_t, 4> QuantizeClampInt8Test(
+        armnn::IWorkloadFactory& workloadFactory,
+        const armnn::IBackendInternal::IMemoryManagerSharedPtr& memoryManager);
+
 LayerTestResult<int16_t, 4> QuantizeClampInt16Test(
     armnn::IWorkloadFactory& workloadFactory,
     const armnn::IBackendInternal::IMemoryManagerSharedPtr& memoryManager);