*  Fix: Don't crash when converting a `HttpUrl` instance with an unresolvable hostname to a URI.
    The new behavior strips invalid characters like `"` and `{` from the hostname before converting.

 *  Fix: Undo a performance regression introduced in OkHttp 4.0 caused by differences in behavior
    between Kotlin's `assert()` and Java's `assert()`. (Kotlin always evaluates the argument; Java
    only does when assertions are enabled.)