RFR: JDK-8144312: Remove limitations on the default number of jobs in the build

[Tim Bell]

Erik:

> The current heuristic for figuring out what to default set the -j flag 
> to make needs some tweaking.
>
> In JDK 9, it looks at the amount of memory and the number of cpus in 
> the system. It divides memory by 1024 to get a safe number of jobs 
> that will fit into memory. The lower of that number and the number of 
> cpus is then picked. The number is then scaled down to about 90% of 
> the number of cpus to leave some resources for other activities. It is 
> also capped at 16.
>
> Since we now have the build using "nice" to make sure the build isn't 
> bogging down the system, I see no reason to do the 90% scaling 
> anymore. Also, the performance issues that forced us to cap at 16 have 
> long been fixed, and even if we don't scale well beyond 16, we do 
> still scale. So I propose we remove that arbitrary limitation too.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8144312
> Webrev: http://cr.openjdk.java.net/~erikj/8144312/webrev.01/

Looks good to me.

/Tim