tests: refactor: rename random_group_element_... -> random_ge_...

The rename was done with the following command:

$ sed -i 's/random_group_element_/random_ge_/g' $(git grep -l random_group_element_)

src/modules/ellswift/tests_impl.h

@@ -229,7 +229,7 @@ void run_ellswift_tests(void) {
         secp256k1_ge g, g2;
         secp256k1_pubkey pubkey, pubkey2;
         /* Generate random public key and random randomizer. */
-        random_group_element_test(&g);
+        random_ge_test(&g);
         secp256k1_pubkey_save(&pubkey, &g);
         secp256k1_testrand256(rnd32);
         /* Convert the public key to ElligatorSwift and back. */