Test for base in references.
* gdb.mi/mi-var-cp.cc: Add test code.
* gdb.mi/mi-var-cp.exp: Test for bases in references.
* gdb.mi/mi-watch.exp: Adjust to mi_runto changes.
* gdb.mi/mi2-watch.exp: Likewise.
* lib/mi-support.exp (mi_runto): Use temporary breakpoint.
(mi_list_varobj_children): New function.