RFR (M): 8201247: Various cleanups in the attach framework

[Langer, Christoph]

Hi,

can I please get reviews for a set of clean up changes that I came across when doing some integration work.

Bug: https://bugs.openjdk.java.net/browse/JDK-8201247
Webrev: http://cr.openjdk.java.net/~clanger/webrevs/8201247.0/

Detailed comments about the changes can be found in the bug.

Thanks & best regards
Christoph