[Skia] Remove bug_880920.pdf from the suppression list

CL [1] has fixed the issue that the dot density in the Skia rendering
result of bug_880920.pdf is way less than its AGG expectation.
Therefore update this corpus test's Skia expectation and remove it
from the suppression list.

[1] https://pdfium-review.googlesource.com/97791

Bug: pdfium:1869
Change-Id: I4c57d7454a39ea2cf856cb5fec334b8738b1332a
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/100613
Commit-Queue: Nigi <nigi@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
diff --git a/DEPS b/DEPS
index 23e3390..91900eb 100644
--- a/DEPS
+++ b/DEPS
@@ -130,7 +130,7 @@
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling pdfium_tests
   # and whatever else without interference from each other.
-  'pdfium_tests_revision': 'b05000cdfc72f339b6e0215f362f1456fa3278de',
+  'pdfium_tests_revision': 'b6972cf63cb584ee0c3ac13a7e21e0374259a0c3',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling resultdb
   # and whatever else without interference from each other.
diff --git a/testing/SUPPRESSIONS b/testing/SUPPRESSIONS
index da537b3..6e5e8e6 100644
--- a/testing/SUPPRESSIONS
+++ b/testing/SUPPRESSIONS
@@ -159,9 +159,6 @@
 # TODO(pdfium:1818): Remove after associated bug is fixed
 bug_691967.pdf * * * skia
 
-# TODO(pdfium:1869): Remove after associated bug is fixed
-bug_880920.pdf * * * skia
-
 bug_white_space.pdf mac * * *
 calcorderindex_test.pdf * * * *
 calculate_average.pdf mac * * *