Fix resolv_{unit,gold}_test linking problem caused by Rust libs

The new linked Rust libs in DnsReoslver caused the
resolv_{unit,gold}_test executive problems due to missing libunwind
symbol.
Add libunwind into whole_static_libs list to fix the problem.

Test: manually run resolv_{unit,gold}_test in Android 10 device
Bug: 193850030
Change-Id: I9013085a20f8fd8bfb8b6f7e9fb7e33a327b98fe