RFR (S): 8140424: don't prefix developer and notproduct flag variables with CONST_ in product builds

[Christian Thalinger]

https://bugs.openjdk.java.net/browse/JDK-8140424 <https://bugs.openjdk.java.net/browse/JDK-8140424>
http://cr.openjdk.java.net/~twisti/8140424/webrev/ <http://cr.openjdk.java.net/~twisti/8140424/webrev/>

When working on JDK-8024545 I added code that prefixes developer and notproduct flags with CONST_. I think I did this to be able to access the address of these variables for the flag table. But this is not necessary because these flag cannot be written anyway. 

I am proposing to remove the CONST_ prefix and define the variables as const.