There is a lot of common code that has been duplicated in */test/Makefile. For jdk, hotspot, jaxp and nashorn, most of the code in the corresponding files are identical. (The odd-man-out is langtools which is quite different.)

These files should be unified to share a single code base, to facilitate further fixing.

The intent of this bug is a pure refactoring. The duplication should go, but all functionality should remain exactly the same. This will leave room for quite a bit of future improvements to the code, but sets a clear limit for this first step.