use unique name for debuginfo gate test

Author: adinn

substratevm/mx.substratevm/mx_substratevm.py

@@ -469,7 +469,7 @@ def svm_gate_body(args, tasks):
                 cinterfacetutorial([])
                 clinittest([])
 
-        with Task('image demos', tasks, tags=[GraalTags.helloworld_debug]) as t:
+        with Task('image demos debuginfo', tasks, tags=[GraalTags.helloworld_debug]) as t:
             if t:
                 if svm_java8():
                     javac_image(['--output-path', svmbuild_dir(), '-H:GenerateDebugInfo=1'])