Remove unused includes from blockfilter.h

This removes unused includes, primitives/block found manually, and the
others by iwyu:

blockfilter.h should remove these lines:
- #include <serialize.h>  // lines 16-16
- #include <undo.h>  // lines 18-18

src/test/util/blockfilter.cpp

@@ -6,6 +6,8 @@
 
 #include <chainparams.h>
 #include <node/blockstorage.h>
+#include <primitives/block.h>
+#include <undo.h>
 #include <validation.h>
 
 using node::BlockManager;