MFC r253910: Add a tunable for the default timeout.

Requested by: rodrigc@, delphij@
MFC r254335: sh: Allow a lone redirection before '|', ';;' or ';&'.

Example: </dev/null | :

PR:		181240
MFC r254231: fnmatch(): Add test for r254353 (pattern with single backslash)

This test cannot be converted to an sh(1) test because the syntax would be
invalid.

r254091 was merged to stable/9 as r254353.

PR:		181129
Merge remote-tracking branch 'upstream-github/stable/9' into stable/9