review: Clean up gradle dependancies and build times

[Kevin Rushforth]

One other change with this patch is in the way API docs are built. Today 
you need to set a flag while building the sdk:

    gradle -PBUILD_JAVADOC=true sdk

With this patch there is a separate task:

    gradle javadoc

-- Kevin


David Hill wrote:
>
> Everyone,
>    this change set should significantly speed up incremental builds as 
> well as fixing some issues we had with bad task deps.
>
> Using a second 'noop/no change'  "gradle sdk" as benchmark, on my 
> virtual windows build, the time drops from around 65 seconds to 
> On my virtual windows build, a second 'gradle sdk' takes ~65, after 
> this change set around 10 seconds.
>
> One risk of this change - I might have missed a dependency. After this 
> goes in tomorrow, please be on the lookout for odd build behavior and 
> let me know.
>
> We have a tool that also help track this....
>
> bash tools/scripts/whatChanged
> does a great job in showing what under ./build changed.
> If something should change and does not ... then we need to correct it.
>
> Kevin,
>    would you review:
>
> jbs: https://bugs.openjdk.java.net/browse/JDK-8172237
> webrev: http://cr.openjdk.java.net/~ddhill/8172237.4/ 
> <http://cr.openjdk.java.net/%7Eddhill/8172237.4/>
> -- 
> David Hill <David.Hill at Oracle.com>
> Java Embedded Development
>
> "A man's feet should be planted in his country, but his eyes should survey the world."
> -- George Santayana (1863 - 1952)
>