base: Add unit test for debug.hh

Add unit tests for the functions and classes in debug.hh.

breakpoint() is not being tested.

Change-Id: I1ae7318a043aa9dc479d4f970c1fd6c9946f4357
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/38710
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/base/SConscript

@@ -40,6 +40,7 @@ Source('channel_addr.cc')
 Source('cprintf.cc', add_tags='gtest lib')
 GTest('cprintf.test', 'cprintf.test.cc')
 Source('debug.cc')
+GTest('debug.test', 'debug.test.cc', 'debug.cc')
 if env['USE_FENV']:
     Source('fenv.c')
 if env['USE_PNG']: