test: cover fastprune with excessive block size

test/functional/test_runner.py

@@ -320,6 +320,7 @@ BASE_SCRIPTS = [
     'feature_includeconf.py',
     'feature_addrman.py',
     'feature_asmap.py',
+    'feature_fastprune.py',
     'mempool_unbroadcast.py',
     'mempool_compatibility.py',
     'mempool_accept_wtxid.py',