Introduce fixNFTokenDirV1 amendment:

o Fixes an off-by-one when determining which NFTokenPage an
  NFToken belongs on.
o Improves handling of packed sets of 32 NFTs with
  identical low 96-bits.
o Fixes marker handling by the account_nfts RPC command.
o Tightens constraints of NFTokenPage invariant checks.

Adds unit tests to exercise the fixed cases as well as tests
for previously untested functionality.

src/test/app/NFTokenBurn_test.cpp

@@ -595,8 +595,11 @@ public:
     run() override
     {
         using namespace test::jtx;
-        auto const sa = supported_amendments();
-        testWithFeats(sa);
+        FeatureBitset const all{supported_amendments()};
+        FeatureBitset const fixNFTDir{fixNFTokenDirV1};
+
+        testWithFeats(all - fixNFTDir);
+        testWithFeats(all);
     }
 };