Fix API mismatch between NameConstraints::IsPermittedCert's subjectAltName...

Fix API mismatch between NameConstraints::IsPermittedCert's subjectAltName param and ParseExtension.

BUG=none

Review URL: https://codereview.chromium.org/1685023002

Cr-Commit-Position: refs/heads/master@{#374826}