To extend LTC (or any Bitcoin Legacy flavor) classical swap tests

[iartemov-ledger]

Currently we've got https://github.com/LedgerHQ/app-exchange/blob/develop/test/python/test_ltc.py.

Locally it can be built and run as follows:

<In app-bitcoin docker>  TARGET=flex BOLOS_SDK=$FLEX_SDK make COIN=litecoin CHAIN=litecoin CAL_TEST_KEY=1 DOMAIN_NAME_TEST_KEY=1 SET_PLUGIN_TEST_KEY=1 NFT_TEST_KEY=1 DEBUG=1

<Inside app-exchange> cp <PATH_TO_app-bitcoin>/build/flex/bin/app.elf test/python/lib_binaries/litecoin_flex.elf

pytest test/python/ --capture=tee-sys --tb=short -v --display --device flex --log_apdu_file=LOG_LTC.txt -k "ltc or litecoin or Litecoin"

In corresponding LOG_LTC.txt (only test/python/test_ltc.py::test_ltc[flex-SubCommand.SWAP_NG] enabled) we see that the test end up by doing INS_HASH_INPUT_FINALIZE_FULL - no INS_SIGN_MESSAGE or further sequence with app-exchange.

To see if it is possible to :

• port test/python/apps/bitcoin_client/ledger_bitcoin/client_legacy.py to Ragger backend
• port the LTC to test/python/apps/exchange_test_runner.py, ExchangeTestRunner framework