JDK 9 RFR of JDK-8172686: Use less aggressive deprecation of utility visitors

[joe darcy]

Hello,

As part of JDK-8050430, the Java SE 6 vintage utility visitors in 
javax.lang.model.util were deprecated. This deprecation is a bit overly 
aggressive; deprecating the constructors of the utility visitors would 
suffice.

Please review the changes to do this:

     http://cr.openjdk.java.net/~darcy/8172686.0/

(I'll change the copyright years to 2017 before pushing.)

Thanks,

-Joe