Test: Gather test execution code in app_broker

This change consolidates all code for tests execution into a single
module named app_broker. The broker creates execution environment for
tests (regression and PSA aPI) requireing the tests implement only
entry functoin: void test_app(void *arg) defined in test_app.h

Signed-off-by: Anton Komlev <anton.komlev@arm.com>
Change-Id: I410f6dd0a635b4b543a25af528195d9365dcf320
diff --git a/app_test_ns/CMakeLists.txt b/app_test_ns/CMakeLists.txt
index 7845d39..3e51212 100644
--- a/app_test_ns/CMakeLists.txt
+++ b/app_test_ns/CMakeLists.txt
@@ -44,8 +44,8 @@
 
 add_executable(tfm_ns)
 
-add_subdirectory(../ns_interface ${CMAKE_BINARY_DIR}/ns_interface)
-add_subdirectory(../test         ${CMAKE_BINARY_DIR}/tests)
+add_subdirectory(../app_broker ${CMAKE_BINARY_DIR}/app_broker)
+add_subdirectory(../test       ${CMAKE_BINARY_DIR}/test)
 
 ############################# TFM NS main app ##################################