Add PDBs to .isolate files so that tests show stack traces.

BUG=405074
R=scottmg@chromium.org
TBR=brettw, davidben

Review URL: https://codereview.chromium.org/468773003

git-svn-id: http://src.chromium.org/svn/trunk/src/base@290612 4ff67af0-8c30-449e-8e8b-ad334ec8d88c