IVGCVSW-2511 Add end to end Gather layer test

 * Add end to end test for Gather operator
 * Add Support for int32 to Constant layer for Ref
 * Add Int32Workload
 * Add RefConstantWorkload as template for float, uint8, int32
 * Remove unused RefBaseConstantWorkload
 * Remove unused RefConstantFloat32Workload
 * Remove unused RefConstantUint8Workload
 * Add support check for int32 in LayerSupport functions

Change-Id: Ic970588a49ebe2aafb12be8adef52371feacaa7b
diff --git a/src/backends/reference/backend.mk b/src/backends/reference/backend.mk
index 8dd6a51..763f26e 100644
--- a/src/backends/reference/backend.mk
+++ b/src/backends/reference/backend.mk
@@ -24,13 +24,11 @@
         workloads/Pooling2d.cpp \
         workloads/RefActivationFloat32Workload.cpp \
         workloads/RefActivationUint8Workload.cpp \
-        workloads/RefBaseConstantWorkload.cpp \
         workloads/RefBatchNormalizationFloat32Workload.cpp \
         workloads/RefBatchNormalizationUint8Workload.cpp \
         workloads/RefBatchToSpaceNdFloat32Workload.cpp \
         workloads/RefBatchToSpaceNdUint8Workload.cpp \
-        workloads/RefConstantFloat32Workload.cpp \
-        workloads/RefConstantUint8Workload.cpp \
+        workloads/RefConstantWorkload.cpp \
         workloads/RefConvertFp16ToFp32Workload.cpp \
         workloads/RefConvertFp32ToFp16Workload.cpp \
         workloads/RefConvolution2dFloat32Workload.cpp \