Test: Remove Library Model codes

Library Model is deprecated, so remove the related codes in test repo.
 - Remove core test since it is Library Model specific.

Signed-off-by: Summer Qin <summer.qin@arm.com>
Change-Id: I5790aa311248b9f0bf4fc3641f29127955a5dd92
diff --git a/docs/tfm_test_suites_addition.rst b/docs/tfm_test_suites_addition.rst
index 99929c5..575e6e2 100644
--- a/docs/tfm_test_suites_addition.rst
+++ b/docs/tfm_test_suites_addition.rst
@@ -112,7 +112,7 @@
 
     #. TF-M partitions configurations like ``TFM_PARTITION_CRYPTO``,
        ``TFM_PARTITION_INITIAL_ATTESTATION``, etc.
-    #. TF-M build mode configuration like ``TFM_LIB_MODEL``.
+    #. TF-M build mode configuration like ``CONFIG_TFM_SPM_BACKEND``.
     #. TF-M other configurations like ``TFM_PARTITION_FIRMWARE_UPDATE``, etc.
 
 #. ``tf-m-tests/config/default_ns_test_config.cmake`` or