waf: define command check as a build shortcut

Now that the concept of programs group is used and 'bin' is the default program
group, the command check needed to be adapted so that (i) it is consistent with
the other build command and (ii) it defines 'all' as its target programs group.

wscript

@@ -187,9 +187,10 @@ def build(bld):
             bld.fatal('check: gtest library is required')
         bld.add_post_fun(ardupilotwaf.test_summary)
 
-class CheckContext(BuildContext):
-    '''executes tests after build'''
-    cmd = 'check'
+ardupilotwaf.build_shortcut('check',
+    program_group_list='all',
+    doc='builds all programs and run tests',
+)
 
 ardupilotwaf.build_shortcut('copter',
     targets='bin/arducopter',