Stop using "legacy" OpenSSL and GnuTLS

None of the tests actually need GNUTLS_LEGACY (3.3.8): GNUTLS (3.4.10)
works.

None of the tests actually need OPENSSL_LEGACY (1.0.1j): OPENSSL (1.0.2g)
works.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/scripts/basic-build-test.sh b/tests/scripts/basic-build-test.sh
index 32be0ee..69b25a4 100755
--- a/tests/scripts/basic-build-test.sh
+++ b/tests/scripts/basic-build-test.sh
@@ -124,9 +124,7 @@
     sh compat.sh
     echo
 
-    echo '#### compat.sh: legacy (null)'
-    OPENSSL="$OPENSSL_LEGACY" \
-    GNUTLS_CLI="$GNUTLS_LEGACY_CLI" GNUTLS_SERV="$GNUTLS_LEGACY_SERV" \
+    echo '#### compat.sh: null cipher'
     sh compat.sh -e '^$' -f 'NULL'
     echo