http: edit _storeHeader to check for Trailer header

Test non-chunked message does not have trailer header set,
message will be terminated by the first empty line after the
header fields, regardless of the header fields present in the
message, and thus cannot contain a message body or 'trailers'.

PR-URL: https://github.com/nodejs/node/pull/12990
Ref: https://github.com/nodejs/node/issues/2842
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Yuta Hiroto <hello@about-hiroppy.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>

lib/internal/errors.js

@@ -155,6 +155,8 @@ E('ERR_PARSE_HISTORY_DATA',
   (oldHistoryPath) => `Could not parse history data in ${oldHistoryPath}`);
 E('ERR_STDERR_CLOSE', 'process.stderr cannot be closed');
 E('ERR_STDOUT_CLOSE', 'process.stdout cannot be closed');
+E('ERR_HTTP_TRAILER_INVALID',
+  'Trailers are invalid with this transfer encoding');
 E('ERR_UNKNOWN_BUILTIN_MODULE', (id) => `No such built-in module: ${id}`);
 E('ERR_UNKNOWN_SIGNAL', (signal) => `Unknown signal: ${signal}`);
 E('ERR_UNKNOWN_STDIN_TYPE', 'Unknown stdin file type');