[BZ 21005] Add support for Intel 64 rdrand and rdseed record/replay

This patch addresses BZ 21005, which is gdb failing to recognize an rdrand
instruction.

It enables support for both rdrand and rdseed and handles extended register
addressing (R8~R15) for 16-bit, 32-bit and 64-bit.

gdb/ChangeLog
2017-02-06  Luis Machado  <lgustavo@codesourcery.com>

	* NEWS: Mention support for record/replay of Intel 64 rdrand and
	rdseed instructions.
	i386-tdep.c (i386_process_record): Handle Intel 64 rdrand and rseed.

gdb/testsuite/ChangeLog:
2017-02-06  Luis Machado  <lgustavo@codesourcery.com>

	* gdb.reverse/insn-reverse.c: Include insn-reverse-x86.c.
	* gdb.reverse/insn-reverse-x86.c: New file.