1.25x speed-up on this microbenchmark:
let o = { get x() { return 1; } };
for (let i = 0; i < 10_000_000; ++i)
o.x;
I looked into this because I noticed getter invocation when profiling
long-running WPT tests. We already had the mechanism for non-getter
properties, and the change to support getters turned out to be trivial.
3c5819a6d2