gdbserver: turn target op 'create_inferior' into a method

gdbserver: turn target op 'create_inferior' into a method

gdbserver/ChangeLog:
2020-02-20  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	Turn process_stratum_target's create_inferior op into a method of
	process_target.

	* target.h (struct process_stratum_target): Remove the target op.
	(class process_target): Add the target op.
	(create_inferior): Rename the macro to ...
	(target_create_inferior): ... this.

	Update the derived classes and callers below.

	* server.cc (handle_v_run): Update.
	(captured_main): Update.
	(process_serial_event): Update.
	* linux-low.cc (linux_target_ops): Update.
	(linux_create_inferior): Turn into ...
	(linux_process_target::create_inferior): ... this.
	* linux-low.h (class linux_process_target): Update.
	* lynx-low.cc (lynx_target_ops): Update.
	(lynx_create_inferior): Turn into ...
	(lynx_process_target::create_inferior): ... this.
	* lynx-low.h (class lynx_process_target): Update.
	* nto-low.cc (nto_target_ops): Update.
	(nto_create_inferior): Turn into ...
	(nto_process_target::create_inferior): ... this.
	* nto-low.h (class nto_process_target): Update.
	* win32-low.cc (win32_target_ops): Update.
	(win32_create_inferior): Turn into ...
	(win32_process_target::create_inferior): ... this.
	* win32-low.h (class win32_process_target): Update.