tests: use (esc) markup for string-escape This makes test output less ambiguous. Failing test output will be escaped and marked up if necessary. A Python string-escape compatible encoding is used, but not everything is encoded - especially not \n and \t and '. [ original upstream message ]

tests: (no-eol) markup for command output without trailing LF Output chunks without a trailing LF will now work but get (no-eol) appended. This change mostly moves code around so we can handle that an output line starts with data from previous command, followed by salt and the next command. [ original upstream message ]