build: remove unused natpmp / upnp cppflags

Their inclusion is likely just the result of copy-paste.

The only place upnp/natpmpflags  should be used is `libbitcoin_node`
(mapport.cpp).

Author: fanquake

src/Makefile.test_fuzz.include

@@ -13,7 +13,7 @@ TEST_FUZZ_H = \
     test/fuzz/mempool_utils.h \
     test/fuzz/util.h
 
-libtest_fuzz_a_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES) $(BOOST_CPPFLAGS) $(MINIUPNPC_CPPFLAGS) $(NATPMP_CPPFLAGS) $(EVENT_CFLAGS) $(EVENT_PTHREADS_CFLAGS)
+libtest_fuzz_a_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES) $(BOOST_CPPFLAGS) $(EVENT_CFLAGS) $(EVENT_PTHREADS_CFLAGS)
 libtest_fuzz_a_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
 libtest_fuzz_a_SOURCES = \
   test/fuzz/fuzz.cpp \

src/Makefile.test_util.include

@@ -20,7 +20,7 @@ TEST_UTIL_H = \
     test/util/validation.h \
     test/util/wallet.h
 
-libtest_util_a_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES) $(BOOST_CPPFLAGS) $(MINIUPNPC_CPPFLAGS) $(NATPMP_CPPFLAGS) $(EVENT_CFLAGS) $(EVENT_PTHREADS_CFLAGS)
+libtest_util_a_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES) $(BOOST_CPPFLAGS) $(EVENT_CFLAGS) $(EVENT_PTHREADS_CFLAGS)
 libtest_util_a_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
 libtest_util_a_SOURCES = \
   test/util/blockfilter.cpp \