OkHostnameVerifier: Don't fall back to CN verification.

The use of Common Name was deprecated in RFC 2818 (May 2000), section 3.1:

  Although the use of the Common Name is existing practice, it is
  deprecated and Certification Authorities are encouraged to use the
  dNSName instead.

This backports upstream commit 52764cb4b9219d699b66e96ccf54db1c37c638bb
from https://github.com/square/okhttp/pull/3764

Bug: 70278814
Test: CtsLibcoreOkHttpTestCases
Change-Id: Iefa8645b93103d70f057a872ac4332147bc2d4d2