Job: receive serialized exception from test

First idea was to use another file descriptor, e.g. 3, in proc_open() but it isn't supported on Windows.

Next idea was to use STDERR, but it is buggy on Windows for STDERR bigger then 2048 (or 4096 depends on PHP version) bytes.
https://bugs.php.net/bug.php?id=51800
https://bugs.php.net/bug.php?id=60120
TapPrinter: standardize format for AssertException