base-stats,tests: Add unit test for Stats::Info

Add a unit test for stats/info.

One test has been disabled due to not knowing the
expected behavior.

It is important to notice that Stats::Info can have
duplicate names using the new style. Stats::Group is
responsible for not allowing duplicate names in this
case.

Change-Id: I8b169d34c1309b37ba79fa9cf6895547b7e97fc0
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/43009
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>

src/base/stats/SConscript

@@ -40,6 +40,7 @@ if env['HAVE_HDF5']:
     else:
         Source('hdf5.cc')
 
+GTest('info.test', 'info.test.cc', 'info.cc', '../debug.cc', '../str.cc')
 GTest('storage.test', 'storage.test.cc', '../debug.cc', '../str.cc', 'info.cc',
     'storage.cc', '../../sim/cur_tick.cc')
 GTest('units.test', 'units.test.cc')