RFR: 8235190 [lworld] Add fastpath to access uninitialized inline fields

[Frederic Parain]

Please review these interpreter changes adding fastpaths when
accessing uninitialized inline fields:

CR: https://bugs.openjdk.java.net/browse/JDK-8235190

Webrev:
http://cr.openjdk.java.net/~fparain/8235190/webrev.00/index.html

Thank you,

Fred