Always suppress DP_CREATE_CLASSLOADER_INSIDE_DO_PRIVILEGED

According to the docs, using AccessController is discouraged:
https://developer.android.com/reference/java/security/AccessController.html

BUG=None

Review-Url: https://codereview.chromium.org/1989403004
Cr-Original-Commit-Position: refs/heads/master@{#395469}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 76a016568a6b224945dd21b04e3eb783673f0e37

android/findbugs_filter/findbugs_exclude.xml

@@ -21,4 +21,9 @@ In particular, ~ at the start of a string means it's a regex.
   <Bug pattern="DM_STRING_CTOR" />
   <!-- Ignore "reliance on default String encoding" warnings, as we're not multi-platform -->
   <Bug pattern="DM_DEFAULT_ENCODING" />
+  <!--
+  Legacy code, discouraged on Android:
+  https://developer.android.com/reference/java/security/AccessController.html
+  -->
+  <Bug pattern="DP_CREATE_CLASSLOADER_INSIDE_DO_PRIVILEGED" />
 </FindBugsFilter>