Fudge persistent legacy hexary db edge case (#1817)

details:
  Persistent pruning would not restore the `emptyRlp` value for the
  root node when the database becomes empty. This effects to an
  assertion exception next time the DB is accessed.

  As most unit tests run on the memory DB, this case slipped through
  unnoticed for a while (see also issue #9.)

nimbus/common/genesis.nim

@@ -45,7 +45,7 @@ proc toGenesisHeader*(
     #
     # This kludge also fixes the initial crash described in
     # https://github.com/status-im/nimbus-eth1/issues/932.
-    if sdb.pruneTrie and 0 < account.storage.len:
+    if sdb.pruneTrie:
       sdb.db.compensateLegacySetup() # <-- kludge
 
     for k, v in account.storage:

tests/test_coredb.nim

@@ -141,10 +141,20 @@ proc coreDbMain*(noisy = defined(debug)) =
 when isMainModule:
   const
     noisy = defined(debug) or true
+    persDb = true
 
   setErrorLevel()
 
-  noisy.legacyRunner()
+  # This one uses the readily available dump: `bulkTest0` and some huge replay
+  # dumps `bulkTest2`, `bulkTest3`, .. from the `nimbus-eth1-blobs` package.
+  # For specs see `tests/test_coredb/bulk_test_xx.nim`.
+  var testList = @[bulkTest0]
+  testList = @[bulkTest1] # This test supersedes `bulkTest0`
+  when true and false:
+    testList = @[bulkTest1, bulkTest2, bulkTest3]
+
+  for n,capture in testList:
+    noisy.legacyRunner(capture=capture, persistent=persDb)
 
 # ------------------------------------------------------------------------------
 # End

tests/test_rocksdb_timing.nim

@@ -281,8 +281,8 @@ when isMainModule:
   setErrorLevel()
 
   # This one uses the readily available dump: `bulkTest0` and some huge replay
-  # dumps `bulkTest1`, `bulkTest2`, .. from the `nimbus-eth1-blobs` package.
-  # For specs see `tests/test_sync_snap/bulk_test_xx.nim`.
+  # dumps `bulkTest2`, `bulkTest3`, .. from the `nimbus-eth1-blobs` package.
+  # For specs see `tests/test_rocksdb_timing/bulk_test_xx.nim`.
   var testList = @[bulkTest0]
   when true and false:
     testList &= @[bulkTest1, bulkTest2, bulkTest3]