support generic test suites not just 'smoke'

This is useful if we want to group our tests in functional suites, like 'io' for IO related tests.

tests/meson.build

@@ -7,7 +7,7 @@ tests = {
 		  'SimplestFibTest.cpp':
 		  {
 			'description': 'Simplest fib test',
-			'smoke_test': true,
+			'test_suite': 'smoke',
 		  },
 
 		  'c_api_test.c':
@@ -50,16 +50,10 @@ foreach source, test_dict : tests
 						link_with: [emper, emper_c],
 					   )
 
-  if test_dict.get('smoke_test', false)
-	test_suite = 'smoke'
-  else
-	test_suite = 'all'
-  endif
-
   test(test_dict.get('description', ''),
 	   test_exe,
 	   is_parallel: test_dict.get('is_parallel', true),
-	   suite: test_suite,
+	   suite: test_dict.get('test_suite', 'all'),
 	   timeout: 60
 	  )
 endforeach