Remove $FreeBSD$: alt two-line .c pattern

Remove /^\s*__RCSID\("\$FreeBSD\$"\);\n\n/

procstat/tests: Fix flakiness by waiting for program to start

Some of the procstat tests start a program "while1" and examine the process
using procstat, but did not wait properly for it to start (kill -0 will
succeed immediately after the child process has been created).

Instead, have "while1" write something when it starts, and use a fifo to
wait for that.

PR: 233587, 233588
Reviewed by: ngie
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D21519

Update the spelling of my name

Previous spellings of my name (NGie, Ngie) weren't my legal spelling. Use Enji
instead for clarity.

While here, remove "All Rights Reserved" from copyrights I "own".

MFC after: 1 week

Start writing up some basic feature tests for procstat

These tests query a running process for information related to the -b,
-c, -e, and -f flags; the -f testcase is largely stubbed out, pending
additional work to determine a good, deterministic descriptor.

Core file test support is coming soon--it requires a bit more effort
due to the fact that:
- coredumps can be disabled (kern.coredump=0).
- corefiles can be put in different directories than the current
directory, or be named something other than `<prog>.core`
(`kern.corefile`).

MFC after: 2 months
Sponsored by: Dell EMC Isilon