bug#51462: sed bug: ASCII NUL not handled in simple pattern

[Frances Wingerter]

I'm using sed 4.8 (`sed (GNU sed) 4.8` per `sed --version`) on x86_64
Arch Linux.

Compare the output of these two sed invocations:
```
$ echo -e 'a\nb\n\0\nc\n' | sed -e '/\0/,$d'
a
b

c

```
and
```
$ echo -e 'a\nb\n\v\nc\n' | sed -e '/\v/,$d'
a
b
```

The latter is the expected behavior, but when input and pattern use
`\0`, sed seems to miss the matches and never triggers.

Hopefully this should be an easy fix.
Thanks,
Frances