RFR: 8166187: Regression: NPE during reparse when using persistent code cache and optimistic types

[Hannes Wallnöfer]

Please review: 

Bug: https://bugs.openjdk.java.net/browse/JDK-8166187
Webrev: http://cr.openjdk.java.net/~hannesw/8166187/webrev/

It was actually the combination of having a non-serialisable AST reference and 
not initialising the transient fields of nested functions that caused this 
error.

Thanks,
Hannes