RFR(S) 8218700: infinite loop in HotSpotJVMCIMetaAccessContext.fromClass after OutOfMemoryError

[dean.long at oracle.com]

https://bugs.openjdk.java.net/browse/JDK-8218700
http://cr.openjdk.java.net/~dlong/8218700/webrev.2/

If we throw an OutOfMemoryError in the right place (see JDK-8222941), 
HotSpotJVMCIMetaAccessContext.fromClass can go into an infinite loop 
calling ClassValue.remove.  To work around the problem, reset the value 
in a mutable cell instead of calling remove.

dl