RFR: JDK-8192067 Add fixpath to test image

[Magnus Ihse Bursie]

To be able to support the use case of running tests using the normal 
make files from prebuilt product and test images, we need to bundle the 
fixpath binary with the test image on Windows.

Bug: https://bugs.openjdk.java.net/browse/JDK-8192067
WebRev: 
http://cr.openjdk.java.net/~ihse/JDK-8192067-add-fixpath-to-test-image/webrev.01

/Magnus