As a result LoadGlobalIC requires different slow stubs for each TypeofMode.

This CL is a prerequisite for not passing variable name to LoadGlobalIC:
the interceptor handler is the only kind of handler that requires a name
and therefore LoadGlobalIC dispatcher does not need a variable name as well.

BUG=chromium:576312

Review-Url: https://codereview.chromium.org/2081143002
Cr-Commit-Position: refs/heads/master@{#37222}