Web load/store buffer size tester

Attempts to find limits for in-flight loads and stores, which
correspond to load/store buffer sizes on some hardware.

This "tool" is mostly for entertainment purposes, at least for
now. Please don't trust it.

The results on M1 are complicated by out-of-order store commit.
I've written more about them on my blog.

Loads on Zen 3 are confusing, I believe others have looked into
this more.