test: add exception in analyze_outcomes.py and fix test for montgomery curves

The exception in analyze_outcomes.py follows previous commit in which
a test in test_suite_pkparse was set with the ECP_C guard for a different
parsing of the private key between the legacy and PSA implementations.

The wrong guard in test_suite_ecp.function instead was erroneously
added in a past commit and it was setting a non-existing symbol of
mbedTLS so those tests were basically never executed.

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/tests/suites/test_suite_ecp.function b/tests/suites/test_suite_ecp.function
index 250efcc..f67c5ae 100644
--- a/tests/suites/test_suite_ecp.function
+++ b/tests/suites/test_suite_ecp.function
@@ -1086,7 +1086,7 @@
 }
 /* END_CASE */
 
-/* BEGIN_CASE depends_on:MBEDTLS_TEST_HOOKS:MBEDTLS_ECP_MONTGOMERY_ENABLED:MBBEDTLS_ECP_C */
+/* BEGIN_CASE depends_on:MBEDTLS_TEST_HOOKS:MBEDTLS_ECP_MONTGOMERY_ENABLED:MBEDTLS_ECP_LIGHT */
 void genkey_mx_known_answer(int bits, data_t *seed, data_t *expected)
 {
     mbedtls_test_rnd_buf_info rnd_info;