- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

dtrace disassembler: take the latest/last CDDL code from OpenSolaris

OpenSolaris version is:
13108:33bb8a0301ab
6762020 Disassembly support for Intel Advanced Vector Extensions (AVX)

This corresponds to Illumos-gate (github) version
ab47273fedff893c8ae22ec39ffc666d4fa6fc8b

MFC after: 3 weeks

r237748 continuation: fix nopw (0f 1f) behavior with respect to modifiers

To do: proper merge with Illumos vendor area.

Reported by: emaste
Tested by: emaste
Obtained from: Illumos commit 13442:4adbe6de60c8
MFC after: 5 days

r237748 continuation: segment-override prefixes are not invalid in long mode

Update DTrace disassembler accordingly. The code to treat the prefixes
as null prefixes was already in place.
Although in practice compilers seem to generate only cs-prefix for use
in long NOPs, the same treatment is applied to all of cs, ds, es, ss for
consistency.

Reported by: emaste
Tested by: emaste
Obtained from: Illumos commit 13442:4adbe6de60c8 (+ local changes)
MFC after: 5 days

dtrace instruction decoder: add 0x0f 0x1f NOP opcode support

According to the AMD manual the whole range from 0x09 to 0x1f are NOPs.
Intel manual mentions only 0x1f. Use only Intel one for now, it seems
to be the one actually generated by compilers.
Use gdb mnemonic for the operation: "nopw".

[1] AMD64 Architecture Programmer's Manual
Volume 3: General-Purpose and System Instructions
[2] Software Optimization Guide for AMD Family 10h Processors
[3] Intel(R) 64 and IA-32 Architectures Software Developer’s Manual
Volume 2 (2A, 2B & 2C): Instruction Set Reference, A-Z

Tested by: Fabian Keil <freebsd-listen@fabiankeil.de> (earlier version)
MFC after: 3 days

Custom DTrace kernel module files plus FreeBSD-specific DTrace providers.