Refactor clone_all_breakpoints

Refactor clone_all_breakpoints

This patch is to change the interface of clone_all_breakpoints, from
lists of breakpoints and raw_breakpoints to child thread and parent
thread.  I choose child thread to pass because we need the ptid of
the child thread in the following patch.

gdb/gdbserver:

2016-07-21  Yao Qi  <yao.qi@linaro.org>

	* inferiors.c (get_thread_process): Make parameter const.
	* inferiors.h (get_thread_process): Update declaration.
	* mem-break.c (clone_all_breakpoints): Remove all parameters.
	Add new parameters child_thread and parent_thread.  Callers
	updated.
	* mem-break.h (clone_all_breakpoints): Update declaration.