strcoll and strxfrm do not always agree in -CURRENT

[Thomas Munro]

Hi,

The PostgreSQL hackers wrote a test program to study a collation bug
on another operating system.  The test generates random strings and
checks if strxfrm and strcoll agree on their ordering, according to
each collation available on the system.  I decided to try it out on
FreeBSD and found that it passes on 10.2, but fails miserably on
11.0-CURRENT.

The test program is here:

http://www.postgresql.org/message-id/19132.1458688784@sss.pgh.pa.us

I had to increase MAXXFRMLEN to (MAXSTRLEN * 10) for it to work.

Thanks!