https://crrev.com/2500363002 updated FunctionTemplate::HasInstance to
follow the hidden prototype chain of a global proxy to the global
object. However, remote contexts don't have a global object to check;
instead, teach the instance check knows about the conventions of
global proxy setup and have it also check the constructor's prototype.

Similarly, also teach Object::FindInstanceInPrototypeChain about the
unusual conventions for remote contexts.

BUG=527190

Review-Url: https://codereview.chromium.org/2698683003
Cr-Commit-Position: refs/heads/master@{#43263}