RFR 8221879 [lworld] Calling convention - Interpreter to C1

[Ioi Lam]

http://cr.openjdk.java.net/~iklam/valhalla/8221879-interp-to-c1.v01/
https://bugs.openjdk.java.net/browse/JDK-8221879

Change the i2c adapter to always go through 
Method::_from_compiled_value_entry.
Removed the StressValueTypePassFieldsAsArgs that's no longer used.
Added test cases.

Question for sharedRuntime_x86_64.cpp:

Should I revert the changes related to gen_i2c_adapter_helper (i.e., 
move the body
of this function back into SharedRuntime::gen_i2c_adapter), to minimize 
the delta
between the jdk/jdk repo and valhalla?


Thanks
- Ioi