Stop infrun from tracking breakpoint insertion status.

The checks of breakpoints_inserted before calling
	remove_breakpoints are removed, as remove_breakpoint
	won't touch uninserted breakpoints. In a number of places,
	we're interested if a breakpoint is inserted at particular
	PC, and we now use breakpoint_inserted_here_p.  In a few
	places, insert_breakpoints can be called unconditionally,
	since it won't try to insert already inserted breakpoint.

	* breakpoint.h (regular_breakpoint_inserted_here_p): New
	declaration.
	* breakpoint.c (regular_breakpoint_inserted_here_p): New.
	(breakpoint_inserted_here_p): Use
	regular_breakpoint_inserted_here_p.
	* infrun.c (breakpoints_inserted): Remove.
	(resume): Don't check for breakpoints_inserted before
	remove_hw_watchpoints. Use breakpoint_inserted_here_p.
	(proceed, init_wait_for_inferior): Don't set breakpoints_inserted.
	(handle_inferior_event): Don't use breakpoints_inserted.
	Use breakpoints_meant_to_be_inserted and
	breakpoints_inserted_here_p.
	(insert_step_resume_breakpoint_at_sal, keep_going): Use
	breakpoints_meant_to_be_inserted. Don't set breakpoints_inserted.
	(normal_stop): Don't check for breakpoints_inserted.  Don't
	set breakpoints_inserted.
	(keep_going): Don't check for breakpoints_inserted.
	(insert_step_resume_breakpoint_at_sal): Don't insert
	breakpoints

gdb/breakpoint.h

@@ -674,6 +674,8 @@ extern enum breakpoint_here breakpoint_here_p (CORE_ADDR);
 
 extern int breakpoint_inserted_here_p (CORE_ADDR);
 
+extern int regular_breakpoint_inserted_here_p (CORE_ADDR);
+
 extern int software_breakpoint_inserted_here_p (CORE_ADDR);
 
 extern int breakpoint_thread_match (CORE_ADDR, ptid_t);