libxml2: upgraded package to upstream

Upgraded dev-libs/libxml2 to version 2.9.12 on amd64

BUG=b/188765489
TEST=presubmit
RELEASE_NOTE=Fixed CVE-2021-3537 in libxml2

Change-Id: I956c257e84c91bafbbc9935aa0b4fa47c19ba4ef
Reviewed-on: https://cos-review.googlesource.com/c/third_party/overlays/portage-stable/+/16791
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Robert Kolchmeyer <rkolchmeyer@google.com>
Reviewed-by: Roy Yang <royyang@google.com>
5 files changed