A DESCRIPTION OF THE PROBLEM :
When building the JDK and running `configure` the output includes (example):
>Build performance summary:
>* Cores to use: 4
>* Memory limit: 32768 MB

The "Cores to use" value is misleading; it is not actually the number of cores specified using `--with-num-cores`, but instead the number of jobs, which (unless explicitly specified), is calculated based on the available memory and the number of cores, see:
- https://github.com/openjdk/jdk/blob/e47803a84feb6d831c6c6158708d29b4fffc99c9/make/autoconf/help.m4#L277
- https://github.com/openjdk/jdk/blob/e47803a84feb6d831c6c6158708d29b4fffc99c9/make/autoconf/build-performance.m4#L141-L145

Requested change:
In the output replace the text "Cores to use" with "Number of parallel jobs" (or similar)