Replace write_inferior_memory with target_write_memory

Replace write_inferior_memory with target_write_memory

target_write_memory is just a simple wrapper for
write_inferior_memory.  Because target_write_memory is needed for
gdbsupport, and because gdb uses the name "target_write_memory"
everywhere, this patch renames write_inferior_memory and removes the
wrapper.  I think this brings gdb and gdbserver slightly more in sync.

gdb/gdbserver/ChangeLog
2019-08-15  Tom Tromey  <tromey@adacore.com>

	* tracepoint.c (write_inferior_data_pointer)
	(write_inferior_integer, write_inferior_int8)
	(write_inferior_uinteger, m_tracepoint_action_download)
	(r_tracepoint_action_download, x_tracepoint_action_download)
	(l_tracepoint_action_download, clear_inferior_trace_buffer)
	(download_agent_expr, download_tracepoint_1)
	(download_trace_state_variables, upload_fast_traceframes): Update.
	* server.c (gdb_write_memory): Update.
	* remote-utils.c (relocate_instruction): Update.
	* proc-service.c (ps_pdwrite): Update.
	* mem-break.c (remove_memory_breakpoint)
	(delete_fast_tracepoint_jump, set_fast_tracepoint_jump)
	(uninsert_fast_tracepoint_jumps_at)
	(reinsert_fast_tracepoint_jumps_at): Update.
	* linux-x86-low.c (append_insns)
	(i386_install_fast_tracepoint_jump_pad)
	(amd64_write_goto_address, i386_write_goto_address): Update.
	* linux-s390-low.c (append_insns, s390_write_goto_address):
	Update.
	* linux-ppc-low.c (ppc_relocate_instruction)
	(ppc_install_fast_tracepoint_jump_pad, emit_insns)
	(ppc_write_goto_address): Update.
	* linux-aarch64-low.c (append_insns): Update.
	* target.h (struct target_ops): Update.
	(write_inferior_memory): Don't declare.
	* target.c (target_write_memory): Rename from
	write_inferior_memory.  Remove old target_write_memory.