Fix for ipv6 link local with scope (1.48.x backport)

[ejona86]

Fix for ipv6 link local with scope. If you try to connect passing address like "ipv6%wlan0" it will use

public SNIHostName(String hostname) {
        super(0, (hostname = IDN.toASCII((String)Objects.requireNonNull(hostname, "Server name value of host_name cannot be null"), 2)).getBytes(StandardCharsets.US_ASCII));
        this.hostname = hostname;
        this.checkHostName();
    }

Which raises hostname is not valid because this method doesn't accept non ASCII characters. With the change it will use

public SNIHostName(byte[] encoded) {
        super(0, encoded);

        try {
            CharsetDecoder decoder = StandardCharsets.UTF_8.newDecoder().onMalformedInput(CodingErrorAction.REPORT).onUnmappableCharacter(CodingErrorAction.REPORT);
            this.hostname = IDN.toASCII(decoder.decode(ByteBuffer.wrap(encoded)).toString());
        } catch (CharacterCodingException | RuntimeException var3) {
            throw new IllegalArgumentException("The encoded server name value is invalid", var3);
        }

        this.checkHostName();
    }

Now scoped ipv6 link is supported. 😄

Backport of #9326