IVGCVSW-4482 Remove boost::ignore_unused

!referencetests:229377

Signed-off-by: Jan Eilers <jan.eilers@arm.com>
Change-Id: Ia9b360b4a057fe7bbce5b268092627c09a0dba82
diff --git a/src/backends/backendsCommon/test/layerTests/GatherTestImpl.cpp b/src/backends/backendsCommon/test/layerTests/GatherTestImpl.cpp
index 6841055..47adb22 100644
--- a/src/backends/backendsCommon/test/layerTests/GatherTestImpl.cpp
+++ b/src/backends/backendsCommon/test/layerTests/GatherTestImpl.cpp
@@ -31,7 +31,7 @@
     const std::vector<int32_t>& indicesData,
     const std::vector<T>& outputData)
 {
-    boost::ignore_unused(memoryManager);
+    IgnoreUnused(memoryManager);
     auto params  = MakeTensor<T, ParamsDim>(paramsInfo, paramsData);
     auto indices = MakeTensor<int32_t, IndicesDim>(indicesInfo, indicesData);