fix(examples/vhdl/array_axis_vcs): use find_prefix_from_path() when determining the backend

Author: umarcor

vunit/test/acceptance/test_external_run_scripts.py

@@ -110,7 +110,7 @@ def test_vhdl_json4vhdl_example_project(self):
     def test_vhdl_array_example_project(self):
         self.check(join(ROOT, "examples", "vhdl", "array", "run.py"))
 
-    @unittest.skipIf(GHDLInterface.determine_backend("") == "mcode",
+    @unittest.skipIf(GHDLInterface.determine_backend(GHDLInterface.find_prefix_from_path()) == "mcode",
                      "mcode backend does not support interfacing with external C code;\n\
                      you should use GCC or LLVM backends")
     def test_vhdl_array_axis_vcs_example_project(self):