Most (all?) released versions of lldb don't support compressed DWARF.
For now, skip the test if lldb can't find where to put the breakpoint.

This is the best I could think of -- there is no explicit error that I
can find that indicates it couldn't load the DWARF.

Fixes #25925.

Change-Id: Ib8fa486a04940cee5959ba7aab7bdbbaa3b2974e
Reviewed-on: https://go-review.googlesource.com/119535
Run-TryBot: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>