RFR: 8187784: IntelliJ langtools project exclusion settings are too broad

[Maurizio Cimadamore]

Hi,
I realized that there's an issue with the langtools IJ project - to make 
it more optimized, I've excluded src/ make/ and test/ folders - to avoid 
indexing and hg overhead (only langtools source folders are then added 
back as source roots). But in doing so, hg support is completely 
disabled, and there's no highlighting in the IDE when a change is made 
to an existing file. So, I'm keeping the build/ exclusion, but dropping 
the others. I also removed an extra root (test) which was only used in 
the previous setup.

http://cr.openjdk.java.net/~mcimadamore/8187784/

Thanks
Maurizio