HTTP: Update the Root Certificate bundle.

Keep 1024-bit legacy root certificates re-added in [35919], except for those already expired, for compatibility with older OpenSSL versions.

Props barry, ayeshrajans, desrosj, whyisjake.
Reviewed by whyisjake, SergeyBiryukov.
Merges [48707] to the 5.5 branch.
See #50828.
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git-svn-id: https://core.svn.wordpress.org/branches/5.5@48470 1a063a9b-81f0-0310-95a4-ce76da25c4cd