This adds an explicit parameter to the call descriptor having kind
kJSCallFunction representing the new.target value. Note that for now
this parameter is not yet passed in and hence cannot be used yet. Also
contains some refactoring of how parameter index value are calculated,
establishing Linkage as the central point for such index computations.

This is a preparatory CL to allows us passing new.target in a register
instead of via a side-channel through the construct stub frame.

R=bmeurer@chromium.org
BUG=v8:4544
LOG=n

Review URL: https://codereview.chromium.org/1461973002

Cr-Commit-Position: refs/heads/master@{#32112}