perf tests: Rename tests/map_groups.c to tests/maps.c

One more step in mergint the maps and map_groups structs.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-bw6aagubqxc47m54k2maezfu@git.kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>