Revert^2 "[ST02.2] Use the getters of DnsHeader"

Reason for revert: November mainline trains has been branched,
                   re-submit CLs and request API review.

Re-submitted Changes:
Ib5616c65c:[ST02.2] Use the getters of DnsHeader
I5e58f99b0:[ST02.1] Add TYPE_CNAME constant to DnsResolver
I0c1547cbc:[ST02] Add methods for synthesizing DNS packets

Change-Id: Ifb727e464d3523bd8dee0f2d919a8fb4a9d207c5
diff --git a/framework/src/android/net/DnsResolver.java b/framework/src/android/net/DnsResolver.java
index 5e637f9..c6034f1 100644
--- a/framework/src/android/net/DnsResolver.java
+++ b/framework/src/android/net/DnsResolver.java
@@ -542,7 +542,7 @@
 
         DnsAddressAnswer(@NonNull byte[] data) throws ParseException {
             super(data);
-            if ((mHeader.flags & (1 << 15)) == 0) {
+            if ((mHeader.getFlags() & (1 << 15)) == 0) {
                 throw new ParseException("Not an answer packet");
             }
             if (mHeader.getRecordCount(QDSECTION) == 0) {