Roll fontconfig to 2.12.6

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Change-Id: I8d0b0827c9622a3ecaaafe33b9784eab201808ef
Reviewed-on: https://chromium-review.googlesource.com/825662
Commit-Queue: Thomas Anderson <[email protected]>
Reviewed-by: Daniel Nicoara <[email protected]>
Cr-Commit-Position: refs/heads/master@{#523918}
11 files changed