IVGCVSW-3824 Implement Float 16 Encoder and Decoder

* Implement Float 16 Encoder and Decoder
* Add Stack Float 16 layer and create workload tests

Signed-off-by: Matthew Jackson <matthew.jackson@arm.com>
Change-Id: Ice4678226f4d22c06ebcc6db3052d42ce0c1bd67
diff --git a/src/backends/backendsCommon/common.mk b/src/backends/backendsCommon/common.mk
index f75870a..39e0265 100644
--- a/src/backends/backendsCommon/common.mk
+++ b/src/backends/backendsCommon/common.mk
@@ -66,6 +66,7 @@
     test/layerTests/SpaceToBatchNdTestImpl.cpp \
     test/layerTests/SpaceToDepthTestImpl.cpp \
     test/layerTests/SplitterTestImpl.cpp \
+    test/layerTests/StackTestImpl.cpp \
     test/layerTests/StridedSliceTestImpl.cpp \
     test/layerTests/SubtractionTestImpl.cpp