Roll libxml to 2677fbf4a4a6dec69ff52265addab713fe48ad1f and libxslt to 840c8e2b6ab33a02374d7a097868649e492da768

This update includes fixes to make calls into libxml cfi-icall safe and
requires rolling libxslt as well. A build change in libxslt enabled
POSIX extended locale support which broke WebKit's expectation that it
overrode libxslt's sorting behavior without any locale modifying code.
I added a patch to enable the old build behavior and disable POSIX
locale support since there did not appear to be an obvious way to fix
WebKit's behavior.

Bug: 779808
Change-Id: Id5baf33879ab37d57892c435f723b809907ea1d9
Reviewed-on: https://chromium-review.googlesource.com/826326
Commit-Queue: Peter Collingbourne <pcc@chromium.org>
Reviewed-by: Scott Graham <scottmg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#528844}
94 files changed