Remove (NE/CL)ComputeAllAnchors function

ComputeAllAnchors is used as part of GenerateProposals and not
standalone thus removes function exposure.

Partially Resolves: COMPMID-3996

Signed-off-by: Georgios Pinitas <georgios.pinitas@arm.com>
Change-Id: I729010b48d747ec40d3ce2c7d0e907e8ec5cd55f
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/4661
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Michele Di Giorgio <michele.digiorgio@arm.com>
diff --git a/tests/validation/CL/GenerateProposalsLayer.cpp b/tests/validation/CL/GenerateProposalsLayer.cpp
index d0ceef5..646a0e0 100644
--- a/tests/validation/CL/GenerateProposalsLayer.cpp
+++ b/tests/validation/CL/GenerateProposalsLayer.cpp
@@ -22,12 +22,13 @@
  * SOFTWARE.
  */
 #include "arm_compute/runtime/CL/CLScheduler.h"
-#include "arm_compute/runtime/CL/functions/CLComputeAllAnchors.h"
 #include "arm_compute/runtime/CL/functions/CLGenerateProposalsLayer.h"
 #include "arm_compute/runtime/CL/functions/CLPermute.h"
 #include "arm_compute/runtime/CL/functions/CLSlice.h"
+#include "src/core/CL/kernels/CLGenerateProposalsLayerKernel.h"
 #include "tests/CL/CLAccessor.h"
 #include "tests/CL/CLArrayAccessor.h"
+#include "tests/CL/Helper.h"
 #include "tests/Globals.h"
 #include "tests/framework/Macros.h"
 #include "tests/framework/datasets/Datasets.h"
@@ -43,6 +44,8 @@
 {
 namespace
 {
+using CLComputeAllAnchors = CLSynthetizeFunction<CLComputeAllAnchorsKernel>;
+
 template <typename U, typename T>
 inline void fill_tensor(U &&tensor, const std::vector<T> &v)
 {