Add empty MSan blacklist.txt to make MSan builds pass.

TBR=fbarchard@chromium.org
BUG=libyuv:564

Review URL: https://codereview.chromium.org/1665573003 .

tools/msan/OWNERS

+pbos@chromium.org
+kjellander@chromium.org
+

tools/msan/blacklist.txt

+# The rules in this file are only applied at compile time.
+# Because the Chrome buildsystem does not automatically touch the files
+# mentioned here, changing this file requires clobbering all MSan bots.
+#
+# Please think twice before you add or remove these rules.
+
+# This is a stripped down copy of Chromium's blacklist.txt, to enable
+# adding libyuv-specific blacklist entries.
+