RFR: CODETOOLS-7902204,7902208: Follow-up generification and misc, part 1,2

[dmitry.bessonov at oracle.com]

Please review the following follow-up fixes related to generics usage in 
JTHarness code; part of the codebase has been cleaned up from casts 
after methods of DynamicArray were generified.

JBS: https://bugs.openjdk.java.net/browse/CODETOOLS-7902204
Webrev: http://cr.openjdk.java.net/~dbessono/7902204/webrev/

JBS: https://bugs.openjdk.java.net/browse/CODETOOLS-7902208
Webrev: http://cr.openjdk.java.net/~dbessono/7902208/webrev/


dmitry