This is another simple test suite change for the parallelization
project.
This changes mi-basics.exp to avoid the use of subdir and objdir and
instead use standard_output_file.
There are still some uses of objdir, but as noted in a new comment in
the patch, these uses are parallel-safe.
* gdb.mi/mi-basics.exp: Use standard_output_file.
(test_dir_specification, test_cwd_specification)
(test_path_specification): Use testsubdir, not subdir and objdir.
