COMPMID-892: OCLGrind failures on both validation and benchmark

-Adds quantization info to the ActivationLayer benchmark fixture
-Replaces clamp with convert_sat in depthwise conv kernel
-Fixes ROIPooling execution slice

Change-Id: Ie9bbe08abcfb8278456964e476b0948247c7ecba
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/118957
Tested-by: Jenkins <bsgcomp@arm.com>
Reviewed-by: Michalis Spyrou <michalis.spyrou@arm.com>
diff --git a/src/core/CL/kernels/CLROIPoolingLayerKernel.cpp b/src/core/CL/kernels/CLROIPoolingLayerKernel.cpp
index 4e000c6..a07a424 100644
--- a/src/core/CL/kernels/CLROIPoolingLayerKernel.cpp
+++ b/src/core/CL/kernels/CLROIPoolingLayerKernel.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017 ARM Limited.
+ * Copyright (c) 2017-2018 ARM Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -108,7 +108,7 @@
     ARM_COMPUTE_ERROR_ON_UNCONFIGURED_KERNEL(this);
     ARM_COMPUTE_ERROR_ON_INVALID_SUBWINDOW(IKernel::window(), window);
 
-    Window slice(window);
+    Window slice = window.first_slice_window_3D();
     // Parallelize spatially and across the fourth dimension of the output tensor (also across ROIArray)
     slice.set(Window::DimZ, window[3]);