RFR: 8352162: Update libxml2 to 2.13.8 [v8]

[Jay Bhaskar]

> The upgrade is required to address several known issues from the previous version to improve stability and performance.

Jay Bhaskar has updated the pull request incrementally with one additional commit since the last revision:

  fix linux build no need extra code

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Changes:
  - all: https://git.openjdk.org/jfx/pull/1785/files
  - new: https://git.openjdk.org/jfx/pull/1785/files/95275e7a..801ba5d0

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1785&range=07
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1785&range=06-07

  Stats: 7 lines in 2 files changed: 0 ins; 3 del; 4 mod
  Patch: https://git.openjdk.org/jfx/pull/1785.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1785/head:pull/1785

PR: https://git.openjdk.org/jfx/pull/1785