* trie: fix error in stacktrie not committing small roots
* fuzzers: make trie-fuzzer use correct returnvalues
* trie: improved tests
* tests/fuzzers: fuzzer for stacktrie vs regular trie
* test/fuzzers: make stacktrie fuzzer use 32-byte keys
* trie: fix error in stacktrie with small nodes
* trie: add (skipped) testcase for stacktrie
* tests/fuzzers: address review comments for stacktrie fuzzer
* trie: fix docs in stacktrie
