Drop HHVM and use the build matrix

[photodude]

HHVM LTS 3.24 is the last version to support PHP 5 compatibility third paragraph states "HHVM will not aim to target PHP7" and further down "We do not intend to be the runtime of choice for folks with pure PHP7 code." (just HACK) https://hhvm.com/blog/2017/09/18/the-future-of-hhvm.html

Use build matrix use sudo false for faster container based testing when sudo is not required for the build

[NinoSkopac]

Cool, thanks

[photodude]

You are welcome.