Merge "Upgrade libxml2 to e1bcffea180d6cc0651757bb64284a763e0e2239" am: e89c501e7f am: 112dac19f1 am: 7a3e4ea229

Original change: https://android-review.googlesource.com/c/platform/external/libxml2/+/1706766

Change-Id: I2ce52c5ae5f65d82054dcfe05b9091e49bbb028d