Use lookups for create_property (ie. new foo.bar)

This is not used that often, but it removes one more place
where we do lookups by name.

Change-Id: I9f798b8b4a64be3fdf3e53090e4288724c9d2b22
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Speed up arguments object

Don't fully create the arguments object unless required.
In the 95% use case, we can avoid creating any array based
data structures for the arguments object and directly
manipulate the functions arguments. only create the full
data structure for the other 5%.

Speeds up the raytrace test by 50%, gives around 10% overall
on v8-bench.

Change-Id: If727d28b96585e83314f544031a6c3ca1817ea19
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Add support for large items to the memory manager

This is required, so we can track ExecutionContexts
through the regular memory manager.

Change-Id: I1bd2e2ef275e6e9e1f364a35affbb991f4377b05
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Turn execution contexts into Managed objects

This finally gives proper memory management for ExecutionContexts.
So far they had been garbage collected but where still allocated
using standard malloc/free(). This allows us to collect the
contexts faster and speed up context creation.

Change-Id: I02e642391d55eaa59ab3f4c2720a2ac71259caf4
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Saner and simpler way to handle line numbers for JITed code

Instead of storing the current instruction pointer in the
ExecutionContext, we might as well directly store the current
line number there.

Leads to simpler code, works cross platform and should also
be faster.

Change-Id: Ifb7897cf8dbe8a962505fe876aa3ed43283ebb06
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>