Fast-path cache line detection via sys prop

[franz1981]

Detecting cache line can be memory and cpu intensive as it is now, involving reading (in-memory) files (in linux) or spawing new processes (on MacOS): in JCTools we save all of this via https://github.com/JCTools/JCTools/blob/a17b56f09cc9ec7d773707578c89f3ca9c11f968/jctools-core/src/main/java/org/jctools/util/PortableJvmInfo.java#L21

1. having a sys prop allow users which support specific archs to save these checks to ever be performed
2. some of these things doesn't change by long time for most architectures

[franz1981]

@radcortez you can add more data about why is costy here, if you wish