Revert "Revert "Enable getaddrinfo parallel lookup by default""

This reverts commit aa483269.

Also set the required tls_frontend option in resolv_gold_test
to make it compatible with parallel_lookup enabled.

Reason for revert: The TLS issue is expected to be solved in aosp/1492679. Re-enable this feature by defualt.

Bug: 168607036
Test: atest

Change-Id: I62b84190006306a63d471c8ccd538bbc32720ab9