Fix step_resume_breakpoint unsaved during an infcall.
* gdbthread.h (struct thread_control_state): Move here field
step_resume_breakpoint ...
(struct thread_info): ... from here.
* infrun.c (save_infcall_control_state): Reset
control.step_resume_breakpoint to NULL.
(restore_infcall_control_state, discard_infcall_control_state): Delete
control.step_resume_breakpoint.
* arm-linux-tdep.c, infrun.c, thread.c: Update all the references to
the moved field.
gdb/testsuite/
Fix step_resume_breakpoint unsaved during an infcall.
* gdb.base/step-resume-infcall.exp: New file.
* gdb.base/step-resume-infcall.c: New file.
