Previously, the species protector was invalidated whenever the __proto__ of
an Array instance was manipulated. Then, if the map's new_target_is_base field
remained set, it was correct to conclude that GetPrototypeOf(array) was
%ArrayPrototype%. However, this choice caused the popular D3 framework to
invalidate the species protector, causing many functions to become slower.

This patch eliminates that aspect of the species protector. Instead, the check
is to look at the instance->map()->prototype(). It is valid to look directly
at the map's prototype slot, ignoring hidden prototypes and proxies, because
- This is only called on Array instances, so the receiver cannot be a Proxy.
- For hidden prototypes, any inaccuracy would only result in conservatively
  taking the slow path.

Theoretically, this patch could make methods applied to arrays from other
contexts slower. However, the slowdown would only affect a particular array
instance and not have a global spill-over effect. Further, the slowdown could
be addressed by tracking, either in the instance's map or in the actual
prototype object, whether it is a %ArrayPrototype% from any context, in a way
which is cheap to query, and use that rather than comparing to the currently
executing native context.

In interactive testing, this patch led the OnShape CAD system to experience
faster load times (110+s -> 40s).

BUG=chromium:606207
LOG=Y

Review-Url: https://codereview.chromium.org/1936393002
Cr-Commit-Position: refs/heads/master@{#36033}