Add test for downstream tethering

Add end-to-end testing for testing NsdManager advertising and
discovering works fine with downstream tethering interfaces.

Bug: 281639507
Test: atest NsdManagerTest
Change-Id: I5a66423f216cfe0c82db5128502c885980ab264b
diff --git a/framework/src/android/net/DnsResolver.java b/framework/src/android/net/DnsResolver.java
index c6034f1..5fefcd6 100644
--- a/framework/src/android/net/DnsResolver.java
+++ b/framework/src/android/net/DnsResolver.java
@@ -77,6 +77,15 @@
     @interface QueryType {}
     public static final int TYPE_A = 1;
     public static final int TYPE_AAAA = 28;
+    // TODO: add below constants as part of QueryType and the public API
+    /** @hide */
+    public static final int TYPE_PTR = 12;
+    /** @hide */
+    public static final int TYPE_TXT = 16;
+    /** @hide */
+    public static final int TYPE_SRV = 33;
+    /** @hide */
+    public static final int TYPE_ANY = 255;
 
     @IntDef(prefix = { "FLAG_" }, value = {
             FLAG_EMPTY,