Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

Check that SCM_XXX timestamp returned by the kernel is less 1 second
away in the past from the current time. This should be plenty for the
scheduler to do its job. It provides assurance that the timestamp
returned is actually a valid one, not just some random garbage.