lib: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

Update the spelling of my name (continuation of r346571)

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

lib/libkvm: start adding basic tests for kvm(3)

- kvm_close: add a testcase to verify support for errno = EINVAL / -1
(see D10065) when kd == NULL is provided to the libcall.
- kvm_geterr:
-- Add a negative testcase for kd == NULL returning "" (see D10022).
-- Add two positive testcases:
--- test the error case using kvm_write on a O_RDONLY descriptor.
--- test the "no error" case using kvm_read(3) and kvm_nlist(3) as
helper routines and by injecting a bogus error message via
_kvm_err (an internal API) _kvm_err was used as there isn't a
formalized way to clear the error output, and because
kvm_nlist always returns ENOENT with the NULL terminator today.
- kvm_open, kvm_open2:
-- Add some basic negative tests for kvm_open(3) and kvm_open2(3).
Testing positive cases with a specific
`corefile`/`execfile`/`resolver` requires more work and would require
user intervention today in order to reliably test this out.

Reviewed by: markj
MFC after: 2 months
Sponsored by: Dell EMC Isilon
Differential Revision: D10024