Test: Simplify regression test build control

Remove TEST_FRAMEWORK_S/NS.
TEST_FRAMEWORK_NS/S can be replaced by the pair of TEST_NS/S_REG_TEST
and NS. It can remove duplicated test flags

Signed-off-by: David Hu <david.hu@arm.com>
Change-Id: Ida6b6dd951c29e0483a276c411d67874317e08ba
diff --git a/docs/tfm_test_suites_addition.rst b/docs/tfm_test_suites_addition.rst
index 9682311..b27ed74 100644
--- a/docs/tfm_test_suites_addition.rst
+++ b/docs/tfm_test_suites_addition.rst
@@ -224,11 +224,9 @@
 
 .. code-block:: cmake
 
-    if (TEST_FRAMEWORK_S)
-        # ...
-        if (TEST_S_<TEST_NAME>)
-            add_library(tfm_test_suite_<test_name>_s STATIC EXCLUDE_FROM_ALL)
-        endif()
+    # ...
+    if (TEST_S_<TEST_NAME>)
+        add_library(tfm_test_suite_<test_name>_s STATIC EXCLUDE_FROM_ALL)
     endif()
 
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