This removes the Javascript version of Array.of in js/array.js and adds
a CodeStubAssembler version in src/builtins/builtins-array-gen.cc.

Mostly this change is for code-health reasons but it also gives
performance improvements for nearly all cases with the exception of
"transplanted" arrays. E.g.
function ArrayLike {}
ArrayLike.of = Array.of
ArrayLike.of(...) is now slower in the perf tests. Most of this change
can be attributed to using CallRuntime(kSetProperty,...) to set the
length. The JS version can do better due to inline caches trained on
the same datatype for 1000s of iterations, but this kind of workload is
unlikely.

Change-Id: I18e5b19b185257e9e0d553e1183b40ba4a5d3289
Reviewed-on: https://chromium-review.googlesource.com/863625
Commit-Queue: Dan Elphick <delphick@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50680}