junk in *grep* buffers

[Dave Love]

Escape sequences appear randomly in *grep* buffers, at least on lines
with two matches.  You can get different results from running the same
grep multiple times, but not reproducibly, and you may not see the
escapes the first time.

Here's an example on a file with the same line repeated thrice.  I
repeated the M-x grep and only got one set of escapes in the buffer
the next time.

-*- mode: grep; default-directory: "/tmp/" -*-
grep -nH -e foo /tmp/x
/tmp/x:1:foo bar foo bar
/tmp/x:2:foo bar foo bar
/tmp/x:3:foo bar foo bar