10 RFR: 8150687: typedefs without type names

[Kim Barrett]

Please review this small change, removing unnecessary uses of "typedef" that 
lead to warnings from Visual Studio 2015.

CR:
https://bugs.openjdk.java.net/browse/JDK-8150687

Webrev:
http://cr.openjdk.java.net/~kbarrett/8150687/jdk.00/

Testing:
jprt