- Add {Map/Set/WeakMap/WeakSet}-Constructor microbenchmarks
- Add {Map/Set}-Double microbenchmarks (testing heap number keys)

Bug: v8:6604
Change-Id: Icadd5c81bfb59a58a2a65e119663d3f22637165d
Reviewed-on: https://chromium-review.googlesource.com/773595Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49398}