Don't call GetMethodID with a pending exception.

Why has no-one been hitting this? Because you'd need your first
getaddrinfo(3) failure to be an EAI_SYSTEM kind of failure, and
you'd need CheckJNI on. So only developers could hit this, and
they'd have to be really unlucky. Like the guy sitting next to me.

Change-Id: I6d2808722eaa50a96ebfa92b996803783601e429