* Fix EVM tracer crash bug when serializing nil stack
* Fix t8n tracer doc
add following description to reflect new functionality
`stdout` - into the stdout output.
`stderr` - into the stderr output.
<file> - into the file <file>-<txIndex>.jsonl.
none - output.basedir/trace-<txIndex>-<txhash>.jsonl.
t8n: a silly bug contract address generator, should use original
tx nonce instead of read the nonce from sender address in state db.
Although in EVM contract address generated by reading nonce from state db
is correct, outside EVM that nonce value might have been modified,
thus generating incorrect contract address.
accounts cache: when clearing account storage, the originalValue
cache is not cleared, only the storageRoot set to empty storage root,
this will cause getStorage and getCommitedStorage return wrong value
if the originalValue cache contains old value.
