Regenerate the long-lived test certificates to use SHA-256

BUG=401365
TBR=mattm

Review URL: https://codereview.chromium.org/515813002

Cr-Commit-Position: refs/heads/master@{#297061}
(cherry picked from commit 80daaf71e46826d627cbf97fe28ce50ceb46a827)

Review URL: https://codereview.chromium.org/621833005

Cr-Commit-Position: refs/branch-heads/2171@{#20}
Cr-Branched-From: 267aeeb8d85c8503a7fd12bd14654b8ea78d3974-refs/heads/master@{#297060}
67 files changed