IVGCVSW-3307 Introduce RefTensorHandle

Use it for intermediate tensors on reference backend.
Lays the groundwork for memory management in the reference backend.

Change-Id: I7d3ee132cac31bde70ae6e1b815f4f0b03d550a6
Signed-off-by: Matthew Bentham <Matthew.Bentham@arm.com>
diff --git a/src/backends/reference/backend.mk b/src/backends/reference/backend.mk
index 7995654..12e5774 100644
--- a/src/backends/reference/backend.mk
+++ b/src/backends/reference/backend.mk
@@ -10,6 +10,7 @@
 BACKEND_SOURCES := \
         RefBackend.cpp \
         RefLayerSupport.cpp \
+        RefTensorHandle.cpp \
         RefWorkloadFactory.cpp \
         workloads/Activation.cpp \
         workloads/BatchNormImpl.cpp \
@@ -78,6 +79,7 @@
 
 BACKEND_TEST_SOURCES := \
         test/RefCreateWorkloadTests.cpp \
+        test/RefDetectionPostProcessTests.cpp \
         test/RefEndToEndTests.cpp \
         test/RefJsonPrinterTests.cpp \
         test/RefLayerSupportTests.cpp \