[unified-heap] Fix CredentialsContainerTest for unified heap GCs

Bug: 902286, 843903
Change-Id: I2f4a836bfb448e092a7301a326c0caed722d607e
Reviewed-on: https://chromium-review.googlesource.com/c/1329175
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606917}
1 file changed