Remove $FreeBSD$: one-line .h pattern

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

Move .../sys/geom/eli/pbkdf2... to .../sys/geom/class/eli/...

This change moves the tests added in r313962 to an existing directory
structure used by the geli TAP tests. It also, renames the test from
pbkdf2 to pbkdf2_test .

The changes to ObsoleteFiles.inc are being committed separately as they
aren't needed for the MFC to ^/stable/11, etc, if the MFC for the tests
is done all in one commit.

MFC after: 2 weeks
X-MFC with: r313962, r313972-r313973
Reviewed by: allanjude
Sponsored by: Dell EMC Isilon
Differential Revision: D9985