vendor/golang.org/x/text: Vendor collate and language

Following the vndr docs [1]:

  $ go get -u github.com/LK4D4/vndr
  $ vndr golang.org/x/text
  $ git add -A vendor/golang.org/x/text

The targeted 'git add' was because we seem to have versioned some test
files (e.g. vendor/github.com/varlink/go/varlink/varlink_test.go in
8493dba (Initial varlink implementation, 2018-03-26, #627).  I don't
know why, possibly an old vndr version?  But either way, I'm punting
that particular issue to a separate branch.

[1]: https://github.com/LK4D4/vndr/blob/1fc68ee0c852556a9ed53cbde16247033f104111/README.md

Signed-off-by: W. Trevor King <[email protected]>

Closes: #686
Approved by: mheon

Author: wking