Build: Improve handling of CMSIS RTX lib

Also add necessary platform files for the core testsuite

Change-Id: Ibfa4ba5f8c0beeca1f333f5be87c8ce8a0910ec9
Signed-off-by: Raef Coles <raef.coles@arm.com>
diff --git a/config/config_default.cmake b/config/config_default.cmake
index e5ad040..31d1ad0 100644
--- a/config/config_default.cmake
+++ b/config/config_default.cmake
@@ -106,6 +106,8 @@
 
 ################################## Tests #######################################
 
+set(TFM_INTERACTIVE_TEST                OFF         CACHE BOOL      "Enable interactive tests")
+
 set(TFM_CRYPTO_TEST_ALG_CBC             ON          CACHE BOOL      "Test CBC cryptography mode")
 set(TFM_CRYPTO_TEST_ALG_CCM             ON          CACHE BOOL      "Test CCM cryptography mode")
 set(TFM_CRYPTO_TEST_ALG_CFB             ON          CACHE BOOL      "Test CFB cryptography mode")