* gdb.mi/mi-stack.c: New file, based on gdb.mi/basics.c.
* gdb.mi/mi-var-child.c: New file, based on gdb.mi/var-cmd.c.
* gdb.mi/mi-stack.exp: Update to use mi-stack.c as a source file.
* gdb.mi/mi-var-child.exp: Update to use mi-var-child.c as a source
file.