Merge pull request #22 from aws-lumberyard-dev/Atom/mnaumov/ATOM-14904_2

[ATOM-14904] Fixing ShaderVariantAsyncLoader shutdown not releasing it's assets

Gems/Atom/RPI/Code/Source/RPI.Public/Shader/ShaderVariantAsyncLoader.cpp

@@ -173,6 +173,7 @@ namespace AZ
             m_serviceThread.join();
             Data::AssetBus::MultiHandler::BusDisconnect();
 
+            m_newShaderVariantPendingRequests.clear();
             m_shaderVariantTreePendingRequests.clear();
             m_shaderVariantPendingRequests.clear();
             m_shaderVariantData.clear();