Remove $FreeBSD$: two-line .h pattern

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

loader.efi: Fix some arm64 PE metadata

- Mark the file as an executable in the COFF header.
- Provide separate .text and .data sections.
- Provide sane file and section alignment values. These values are the
defaults defined in the PE specification.
- Set appropriate characteristics for each of .text and .data.

This is required for the MS devkit to load our UEFI image.

Obtained from: OpenBSD via allanjude
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D37765

Use adrp in the arm64 efi loader

On startup the arm64 efi loaders need to know PC-relative addresses.
Previously we used the adr instruction to find this address, however this
instruction is limited to +/- 1MiB.

Switch to adrp to find the 4k page the address is within and an add to
set the bottom 12 bits. This lets us address +/- 4GiB which should be
large enough for now.

Reported by: imp
MFC after: 2 weeks
Sponsored by: Innovate UK

Ensure we have a large enough stack for the lua loader

Lua has a few places where it allocates a large buffer on the stack. This
is normally fine, except there are a few places where there can be multiple
frames with this buffer. This can cause a stack overflow on some arm64 SoCs.

Fix this by allocating our own stack in loader.efi large enough for these
objects. The required size has been found by tracing how the stack pointer
changes in a virtual machine and found to be no larger than 50kB. A
larger stack is allocated to reduce the likelihood of overflow from future
changes.

Reviewed by: kevans
Approved by: re (kib)
Differential Revision: https://reviews.freebsd.org/D16886

Move sys/boot to stand. Fix all references to new location

Sponsored by: Netflix