Update rtos CMake to include greentea test dir

Author: rajkan01

rtos/CMakeLists.txt

@@ -3,7 +3,7 @@
 
 if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME AND BUILD_TESTING)
     if(BUILD_GREENTEA_TESTS)
-        # add greentea test
+        add_subdirectory(tests/TESTS)
     else()
         add_subdirectory(tests/UNITTESTS)
     endif()

rtos/tests/TESTS/CMakeLists.txt

@@ -0,0 +1,17 @@
+# Copyright (c) 2021 ARM Limited. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+add_subdirectory(mbed_rtos/basic)
+add_subdirectory(mbed_rtos/condition_variable)
+add_subdirectory(mbed_rtos/event_flags)
+add_subdirectory(mbed_rtos/heap_and_stack)
+add_subdirectory(mbed_rtos/kernel_tick_count)
+add_subdirectory(mbed_rtos/mail)
+add_subdirectory(mbed_rtos/malloc)
+add_subdirectory(mbed_rtos/MemoryPool)
+add_subdirectory(mbed_rtos/mutex)
+add_subdirectory(mbed_rtos/queue)
+add_subdirectory(mbed_rtos/semaphore)
+add_subdirectory(mbed_rtos/signals)
+add_subdirectory(mbed_rtos/systimer)
+add_subdirectory(mbed_rtos/threads)