Outdated readme files in jdk9 repository

[Anthony Vanelverdinghe]

Hi

While looking for README-builds.html, I came across the following 
outdated README: http://hg.openjdk.java.net/jdk9/jdk9/jdk/file/tip/README
An equally outdated file is in the langtools repository: 
http://hg.openjdk.java.net/jdk9/jdk9/langtools/file/tip/README
In my opinion, these should be updated, analog to what was done in the 
other repositories (corba, hotspot, etc.)

On a side note, the OpenJDK page of the build group [1] contains 2 
broken links:

"OpenJDK7 Build README" should link to 
http://hg.openjdk.java.net/jdk7u/jdk7u/raw-file/tip/README-builds.html
"OpenJDK8 Build README" should link to 
http://hg.openjdk.java.net/jdk8u/jdk8u/raw-file/tip/README-builds.html

And it might also be useful to add a link for OpenJDK9: 
http://hg.openjdk.java.net/jdk9/jdk9/raw-file/tip/README-builds.html

[1] http://openjdk.java.net/groups/build/

Kind regards,
Anthony