Redmine#3584: add "make check" target that takes TESTS parameter

See https://cfengine.com/dev/issues/3584

~~Requires the `@include` mechanism from https://github.com/cfengine/core/pull/902~~

Reworked as suggested by @kacfengine and in conjunction with https://github.com/cfengine/core/pull/1058

@cduclos @kacfengine @nickanderson please review