Roll PDFium from 1443e5ac0acf to af6371f32764 (2 revisions)

https://pdfium.googlesource.com/pdfium.git/+log/1443e5ac0acf..af6371f32764

2020-11-02 tsepez@chromium.org Consolidate some tests in new fxv8:: functions.
2020-11-02 nigi@chromium.org Fix issue that some characters from the embedded font don't render.

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/pdfium-autoroll
Please CC pdfium-deps-rolls@chromium.org on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/master/autoroll/README.md

Bug: None
Tbr: pdfium-deps-rolls@chromium.org
Change-Id: Ia6f22975aa393d189816ddfd9dc96df61b2d5bff
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2515083Reviewed-by: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#823404}

DEPS

@@ -226,7 +226,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling PDFium
   # and whatever else without interference from each other.
-  'pdfium_revision': '1443e5ac0acfb54ef2b6c2da3b26a8758bac1e6a',
+  'pdfium_revision': 'af6371f3276419d16bcf1f97f8e1b88041812f9f',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling BoringSSL
   # and whatever else without interference from each other.