COMPMID-3227: Review documentation

- Rework directory layout in introduction and tests
- Remove notes around CL/OpenGLES stubs as we now use dlopen

Signed-off-by: Georgios Pinitas <georgios.pinitas@arm.com>
Change-Id: Iab824719af3f3b20449ddc0348c40066b63d4bc2
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/2891
Reviewed-by: Gian Marco Iodice <gianmarco.iodice@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
diff --git a/docs/02_tests.dox b/docs/02_tests.dox
index 02c3c8e..b636880 100644
--- a/docs/02_tests.dox
+++ b/docs/02_tests.dox
@@ -1,5 +1,5 @@
 ///
-/// Copyright (c) 2017-2019 ARM Limited.
+/// Copyright (c) 2017-2020 ARM Limited.
 ///
 /// SPDX-License-Identifier: MIT
 ///
@@ -50,20 +50,20 @@
     .
     `-- tests <- Top level test directory. All files in here are shared among validation and benchmark.
         |-- framework <- Underlying test framework.
-        |-- CL   \
+        |-- CL             \
+        |-- GLES_COMPUTE   \
         |-- NEON -> Backend specific files with helper functions etc.
         |-- benchmark <- Top level directory for the benchmarking files.
         |   |-- fixtures <- Fixtures for benchmark tests.
         |   |-- CL <- OpenCL backend test cases on a function level.
-        |   |   `-- SYSTEM <- OpenCL system tests, e.g. whole networks
+        |   |-- GLES_COMPUTE <- Same of OpenGL ES
         |   `-- NEON <- Same for NEON
-        |       `-- SYSTEM
         |-- datasets <- Datasets for benchmark and validation tests.
         |-- main.cpp <- Main entry point for the tests. Currently shared between validation and benchmarking.
-        |-- networks <- Network classes for system level tests.
         `-- validation -> Top level directory for validation files.
             |-- CPP -> C++ reference code
-            |-- CL   \
+            |-- CL             \
+            |-- GLES_COMPUTE   \
             |-- NEON -> Backend specific test cases
             `-- fixtures -> Fixtures shared among all backends. Used to setup target function and tensors.