RFR: JDK-8206125: [windows] cannot pass relative path to --with-boot-jdk

[Tim Bell]

Erik:

> On Windows, the BASIC_FIXUP_PATH macro in configure does not actually 
> convert relative paths to absolute like the description claims. This 
> patch takes the implementation already present for Unix and applies it 
> to all the different Windows environment specific implementations. I 
> have verified that it's now possible to use relative paths as well as ~ 
> based paths in both Cygwin and WSL for the --with-jtreg parameter, and 
> relative paths for --with-boot-jdk.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8206125
> 
> Webrev: http://cr.openjdk.java.net/~erikj/8206125/webrev.01/

Looks good.

Tim