RFR(S): JDK- 8136718: [TESTBUG] introduce FileInstaller functionality

[Dmitrij]

Hi,

please review a small enchancement:
JDK-8136718: [TESTBUG] introduce FileInstaller functionality.

Description:
A FileInstaller is a functionality to install some file resources from 
test.src-relative directory into test working directory or 
subdirectory(needed for upcoming tests).

webrev: http://cr.openjdk.java.net/~dpochepk/8136718/webrev.8136718.01/


Thanks,
Dmitrij