Re-structure Atom test folders in AutomatedTesting. (#4206)

* move shader asset builder test into test_Atom_MainSuite_Optimized.py, update CMakeLists.txt, and move all imports inside the test class for hydra_ShaderAssetBuilder_RecompilesShaderAsChainOfDependenciesChanges.py

Signed-off-by: jromnoa <jromnoa@amazon.com>

* re-organize the Atom automated test structure to match the new parallel + batched test structures

Signed-off-by: jromnoa <jromnoa@amazon.com>

* fix CMakeLists.txt registrations for test files

Signed-off-by: jromnoa <jromnoa@amazon.com>

AutomatedTesting/Gem/PythonTests/Atom/TestSuite_Sandbox.py

@@ -0,0 +1,20 @@
+"""
+Copyright (c) Contributors to the Open 3D Engine Project.
+For complete copyright and license terms please see the LICENSE at the root of this distribution.
+
+SPDX-License-Identifier: Apache-2.0 OR MIT
+
+Sandbox suite tests for the Atom renderer.
+"""
+
+import pytest
+
+
+@pytest.mark.parametrize("project", ["AutomatedTesting"])
+@pytest.mark.parametrize("launcher_platform", ['windows_editor'])
+@pytest.mark.parametrize("level", ["auto_test"])
+class TestAtomEditorComponentsSandbox(object):
+
+    # It requires at least one test
+    def test_Dummy(self, request, editor, level, workspace, project, launcher_platform):
+        pass