bug#16525: 24.3; Weird font-lock for multi-line regexp

[Alex Kost]

When I try to use a multi-line regexp in `font-lock-keywords', I have an
unusual result: some lines are highlighted and some are not (lines are
the same).

I have made a test mode, a text sample and a screenshot to show how it
looks for me when tested with "emacs -Q".

Recipe:
1. emacs -Q
2. Evaluate the contents of attached "test.el"
3. "M-x test-font-lock-mode" in a buffer with attached "sample"

test.el
Description: application/emacs-lisp

sample
Description: Text document

2014-01-23_115015.png
Description: PNG image

In GNU Emacs 24.3.1 (i686-pc-linux-gnu, GTK+ Version 3.8.2)
 of 2013-08-07 on -mnt-storage-buildroots-staging-i686-eric
Windowing system distributor `The X.Org Foundation', version 11.0.11405000
Configured using:
 `configure '--prefix=/usr' '--sysconfdir=/etc' '--libexecdir=/usr/lib'
 '--localstatedir=/var' '--with-x-toolkit=gtk3' '--with-xft'
 'CFLAGS=-march=i686 -mtune=generic -O2 -pipe -fstack-protector
 --param=ssp-buffer-size=4'
 'LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro'
 'CPPFLAGS=-D_FORTIFY_SOURCE=2''

Important settings:
  value of $LC_COLLATE: C
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t