Refactor existing tests to use new mixin classes

reframe_tests/tests/standard_tests.py

@@ -1,6 +1,10 @@
 from reframe_tests.tests.base_tests import GprMaxBaseTest
-from reframe_tests.tests.mixins import ReceiverMixin
+from reframe_tests.tests.mixins import ReceiverMixin, SnapshotMixin
 
 
 class GprMaxRegressionTest(ReceiverMixin, GprMaxBaseTest):
     pass
+
+
+class GprMaxSnapshotTest(SnapshotMixin, GprMaxBaseTest):
+    pass