If an ; or & token was followed by an EOF token, pending here-documents were
left uninitialized. Execution would crash, either in the main shell process
for literal here-documents or in a child process for expanded
here-documents. In the latter case the problem is hard to detect apart from
the core dumps and log messages.
Side effect: slightly different retries on inputs where EOF is not
persistent.
Note that tools/regression/bin/sh/parser/heredoc6.0 still causes a similar
crash in a child process. The text passed to eval is malformed and should be
rejected.
f8f703f788