There's actually no point trying to do Function.prototype.toString in
JavaScript, as it always calls into C++ at least once, so it only
complicates things (esp. once we start optimizing bound functions).

Drive-by-fix: Rename FunctionApply and FunctionCall builtins to also
reflect the fact that these are builtins in the Function.prototype and
not on Function itself.

TBR=hpayer@chromium.org
R=yangguo@chromium.org
BUG=chromium:535408
LOG=n

Review URL: https://codereview.chromium.org/1540953004

Cr-Commit-Position: refs/heads/master@{#32996}