sh: Do not read from stdin if an error occurs during -i -c cmd.

Although using -i with -c does not seem very useful, it seems inappropriate
to read commands from the terminal in this case.

Side effect: if the -s -c extension is used and the -s option is turned off
using 'set +s' during the interactive part, the shell now exits after an
error or interrupt. Note that POSIX only specifies -s as option to sh, not
to set.

See also Austin Group issue #718.
Fix check: bitwise and has only one &.

MFC after:	1 week