Fix CVE-2016-0718: Expat XML Parser Crashes on Malformed Input

Includes all changes made on the cve-2016-0718-fix-2-2-1 branch
that was merged into the master branch in commit
be4b1c06daba1849b8ff5e00bae5caf47f6c39fd
in repository http://git.code.sf.net/p/expat/code_git

(cherry picked from commit 7b64b72da916c9c9c285939c11f81de938268fa9)

Bug: 28698301
Change-Id: I9fe93040b3a9afb04be63c5fd453a2b99c01fb37
(cherry picked from commit 4bf8f12b1d505770ce1fd3b5aa33bd7abe46ee74)