RFR: 8193472 [Valhalla] Interpreter should be able to return values in TLVB

[Frederic Parain]

Please, review this fix to improve the way values are returned by the interpreter,
using the Thread-Local Value Buffer whenever possible. The return in the TLVB
is currently disabled, because some fixes are required in JIT code.

CR:
https://bugs.openjdk.java.net/browse/JDK-8193472

Webrev:
http://cr.openjdk.java.net/~fparain/8193472/webrev.00/index.html

Thank you,

Fred