Class-fy dwarf2_frame_state_reg_info

Class-fy dwarf2_frame_state_reg_info

This patch adds dwarf2_frame_state_reg_info ctor, dtor, copy ctor,
assignment operator, and move assignment.  This patch also adds unit test
to execute_cfa_program to cover the changes.

gdb:

2017-08-11  Yao Qi  <yao.qi@linaro.org>

	* dwarf2-frame.c (dwarf2_frame_state_alloc_regs): Remove.
	(dwarf2_frame_state_copy_regs): Remove.
	(dwarf2_frame_state_free_regs): Remove.
	(dwarf2_frame_state::~dwarf2_frame_state): Remove.
	(dwarf2_restore_rule): Call method .alloc_regs instead of
	dwarf2_frame_state_alloc_regs.
	(execute_cfa_program): Likewise.  Call dwarf2_frame_state_reg_info
	constructor.  Call std::move.
	(dwarf2_fetch_cfa_info): Don't call dwarf2_frame_state_copy_regs.
	(dwarf2_frame_cache): Likewise.

	[GDB_SELF_TEST]: Include selftest.h and
	selftest-arch.h.
	[GDB_SELF_TEST] (execute_cfa_program_test): New function.
	(_initialize_dwarf2_frame) [GDB_SELF_TEST]: Register
	execute_cfa_program_test.

	* dwarf2-frame.h (dwarf2_frame_state_reg_info): Add ctor, dtor,
	copy ctor, assignment operator, move assignment.
	<alloc_regs>: New method.
	<swap>: New method.
	(struct dwarf2_frame_state): Delete dtor.
	(dwarf2_frame_state_alloc_regs): Remove declaration.
	* sparc-tdep.c (sparc_execute_dwarf_cfa_vendor_op): Don't call
	dwarf2_frame_state_alloc_regs, use .alloc_regs instead.