Fix asynchronous DNS API flag NO_CACHE_LOOKUP behavior

Previously, this flag won't store response into cache.
Fix it to store the response into cache.
If the entry is already in the cache, ignore storing.

Bug: 122574655

Test: built, flashed, booted
      system/netd/tests/runtests.sh pass
      atest CtsNativeNetDnsTestCases
      atest DnsResolverTest

Change-Id: Ia25fc0601013823c85344a3ca2a9c74e5b2a21a3