test: disable BIGNUM support on the test ecc_no_bignum component

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 9823e42..38fbc2b 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -2673,7 +2673,8 @@
         scripts/config.py unset MBEDTLS_ECJPAKE_C
         # Disable ECP module (entirely)
         scripts/config.py unset MBEDTLS_ECP_C
-        # TODO: bignum
+        # Also disable bignum
+        scripts/config.py unset MBEDTLS_BIGNUM_C
     fi
 
     # Disable all the features that auto-enable ECP_LIGHT (see build_info.h)
@@ -2763,6 +2764,7 @@
     not grep mbedtls_ecp_ library/ecp.o
     not grep mbedtls_rsa_ library/rsa.o
     not grep mbedtls_dhm_ library/dhm.o
+    not grep mbedtls_mpi_ library/bignum.o
 
     # Run the tests
     # -------------