fw: delegate sending Nack-Duplicate to forwarding strategy

This commit introduces a new strategy trigger (onInterestLoop) that
is invoked when a duplicate Interest is received. The default behavior
of the new trigger is to send a Nack as before. We also modify the
MulticastStrategy to override onInterestLoop and skip sending the Nack.

Refs: #5278
Co-authored-by: Davide Pesavento <davidepesa@gmail.com>
Change-Id: I07bb520bd31cbfc8d8f8581e05c49927f8ea35f7
diff --git a/tests/daemon/fw/strategy-instantiation.t.cpp b/tests/daemon/fw/strategy-instantiation.t.cpp
index 535b4b0..ae18eea 100644
--- a/tests/daemon/fw/strategy-instantiation.t.cpp
+++ b/tests/daemon/fw/strategy-instantiation.t.cpp
@@ -64,7 +64,7 @@
   Test<AccessStrategy, false, 1>,
   Test<AsfStrategy, true, 5>,
   Test<BestRouteStrategy, true, 5>,
-  Test<MulticastStrategy, true, 4>,
+  Test<MulticastStrategy, true, 5>,
   Test<SelfLearningStrategy, false, 1>,
   Test<RandomStrategy, false, 1>
 >;