Keep ubsan ignorelist.txt to use regex

Add "#!special-case-list-v1" in the file to use regex, otherwise it will use glob.

Bug: chromium:1515966
Change-Id: Idd7dd320695331fb33d5e80cbd627bc49be0cb3a
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/115430
Auto-Submit: Zequan Wu <zequanwu@google.com>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Nigi <nigi@chromium.org>
diff --git a/tools/ubsan/ignorelist.txt b/tools/ubsan/ignorelist.txt
index 7a2271d..e140fc5 100644
--- a/tools/ubsan/ignorelist.txt
+++ b/tools/ubsan/ignorelist.txt
@@ -1,3 +1,6 @@
+#!special-case-list-v1
+# TODO(https://crbug.com/1515966): update to glob patterns
+
 #############################################################################
 # UBSan ignore list.
 
diff --git a/tools/ubsan/security_ignorelist.txt b/tools/ubsan/security_ignorelist.txt
index 30f66a4..df60337 100644
--- a/tools/ubsan/security_ignorelist.txt
+++ b/tools/ubsan/security_ignorelist.txt
@@ -1,3 +1,6 @@
+#!special-case-list-v1
+# TODO(https://crbug.com/1515966): update to glob patterns
+
 # This ignore  list is a merge of ignorelist.txt and vptr_ignorelist.txt.
 
 #############################################################################