Conscrypt fails on _ in domain name

These hosts work from firefox

Reported here https://github.com/square/okhttp/issues/5840

https://open_nsfw.gitlab.io/ (which was highly circulated on the web a few years ago)
https://example_underscore_123.s3.amazonaws.com/
https://instant_regret.reddit.com/

```
java.lang.IllegalArgumentException: Invalid input to toASCII: example_underscore.s3.amazonaws.com
at java.net.IDN.toASCII(IDN.java:115)
at javax.net.ssl.SNIHostName.(SNIHostName.java:99)
at com.android.org.conscrypt.Platform.getSSLParameters(Platform.java:153)
at com.android.org.conscrypt.ConscryptFileDescriptorSocket.getSSLParameters(ConscryptFileDescriptorSocket.java:1117)
at okhttp3.internal.platform.Android10Platform.configureTlsExtensions(Android10Platform.java:40)
```