automerge_perf LwwMap analogs for other libs

[mweidner037]

Our LwwMap-as-text benchmark is understandably less efficient than CText. It would be interesting to implement analogous benchmarks for Automerge and Yjs.

I recall for Automerge, using a string[] is about the same as using Automerge.Text. For Yjs, there could be a slowdown (https://discuss.yjs.dev/t/moving-elements-in-lists/92/14).