[stable] Backports (#8557)

* Update wasmi and pwasm-utils (#8493)

* Update wasmi to 0.2

New wasmi supports 32bit platforms and no longer requires a special feature to build for such platforms.

* Update pwasm-utils to 0.1.5

* Fetching logs by hash in blockchain database (#8463)

* Fetch logs by hash in blockchain database

* Fix tests

* Add unit test for branch block logs fetching

* Add docs that blocks must already be sorted

* Handle branch block cases properly

* typo: empty -> is_empty

* Remove return_empty_if_none by using a closure

* Use BTreeSet to avoid sorting again

* Move is_canon to BlockChain

* typo: pass value by reference

* Use loop and wrap inside blocks to simplify the code

Borrowed from https://github.com/paritytech/parity/pull/8463#discussion_r183453326

* typo: missed a comment

* Pass on storage keys tracing to handle the case when it is not modified (#8491)

* Pass on storage keys even if it is not modified

* typo: account and storage query

`to_pod_diff` builds both `touched_addresses` merge and storage keys merge.

* Fix tests

* Use state query directly because of suicided accounts

* Fix a RefCell borrow issue

* Add tests for unmodified storage trace

* Address grumbles

* typo: remove unwanted empty line

* ensure_cached compiles with the original signature

* Enable WebAssembly and Byzantium for Ellaism (#8520)

* Enable WebAssembly and Byzantium for Ellaism

* Fix indentation

* Remove empty lines

* Fix compilation.

ethcore/src/verification/verification.rs

@@ -458,7 +458,7 @@ mod tests {
 			unimplemented!()
 		}
 
-		fn logs<F>(&self, _blocks: Vec<BlockNumber>, _matches: F, _limit: Option<usize>) -> Vec<LocalizedLogEntry>
+		fn logs<F>(&self, _blocks: Vec<H256>, _matches: F, _limit: Option<usize>) -> Vec<LocalizedLogEntry>
 			where F: Fn(&LogEntry) -> bool, Self: Sized {
 			unimplemented!()
 		}