Tests n_172 and n_175 are the same

[nicowilliams]

Tests like parsers/test_ccan_json/json/_test/nst_files/n_31.json (of which there are many) fail with jq only because jq permits multiple JSON texts in one input stream.

I'm not saying this is permissible JSON, just that it's an entire category of tests that jq will always fail (by design), so it would be best to separate them, kinda like i_* tests.

$ sha256sum parsers/test_ccan_json/json/_test/nst_files/n_17[25].json
c28f64ade65fab04e9ced46a826c6779188f7754c604fb3f4c3e8b80e3418148  parsers/test_ccan_json/json/_test/nst_files/n_172.json
c28f64ade65fab04e9ced46a826c6779188f7754c604fb3f4c3e8b80e3418148  parsers/test_ccan_json/json/_test/nst_files/n_175.json
$