Implement ICs for constructor calls.

Implement ICs for constructor calls.

This reuses the CallIC machinery for calling functions as constructors
by flagging those CallICs with a bit in the ExtraICState. The CallIC in
turn will dispatch to the function-specific construct stub. It also
introduces new base class (i.e. CallBase) for all AST nodes having a
call-like semantic (i.e. Call and CallNew).

R=kmillikin@chromium.org

[Michael Starzinger, 2011-12-08 10:22:18]

This only works on IA32 so far, but I wanted to get a first round of reviews
before I start porting it to other architectures.

[Kevin Millikin (Chromium), 2011-12-08 11:15:19]

My high level comment is that I'm skeptical that this is the right approach. 
You will need to convince me.

This treats function-valued object properties, when called as constructors, as
methods of the object holding them.  I don't think that's quite right and I can
see problems down the line.

It misses the common use of constructors which are not properties of any object.
 We will want to optimize that case, and I don't think we want two different
mechanisms.

Another downside of this approach is that we only know the function identity
from the map for CONSTANT_FUNCTION, not FIELD.  I think we'll want to optimize
the field case, too.

Maybe a better approach is to record monomorphic constructor function identity
at the call site, like we do with the CallFunctionStub.

(As an aside, we will have to change our handling of CallIC sometime in order to
support the ES5 semantics.  When we do that, and with this change, we will
either end up with the wrong semantics for these constructors, or else two modes
of CallICs, or else a new infrastructure for method calls and keeping all the
old CallIC code around just to support this case.)

[Michael Starzinger, 2012-01-27 16:31:05]

For record: This CL was superseded by another one. We now use global property
cells instead of ICs to get type feedback for constructor calls.

https://chromiumcodereview.appspot.com/8932004/