The semantics of the %_CallFunction intrinsic seem to be very unclear,
which resulted in a lot of bugs. Especially the combination with
%IsSloppyModeFunction is always a bug, because the receiver would be
wrapped in the wrong context. So the %IsSloppyModeFunction helper is
gone now, and many of the buggy uses of %_CallFunction are also
eliminated.

If you ever need to call something with a different receiver, then
%_Call is your friend now. It does what you want and implements the
call sequence fully (and correct).

BUG=v8:4413
LOG=n

Review URL: https://codereview.chromium.org/1325573004

Cr-Commit-Position: refs/heads/master@{#30634}