[lworld] Cleanup: remove TypeValueTypePtr

[Tobias Hartmann]

Hi,

please review this cleanup change that removes TypeValueTypePtr and uses TypeInstPtr instead:
http://cr.openjdk.java.net/~thartmann/valhalla/lworld/cleanup3/

The relevant changes are in type.cpp/hpp, the rest is refactoring. All tests pass.

Thanks,
Tobias