crypto/x509: Certificate no longer encodable using encoding/gob in Go1.22 [1.22 backport]

[gopherbot]

@rsc requested issue #65633 to be considered for backport to the next 1.22 minor release.

@gopherbot please backport go1.22

[gopherbot]

Change https://go.dev/cl/571715 mentions this issue: [release-branch.go1.22] encoding/gob: make x509.Certificate marshalable again

[thanm]

Discussed in the release checkin meeting ->approved.

[gopherbot]

Closed by merging 0a5b33a to release-branch.go1.22.