Fixes the following error in the testcase:
File "/usr/lib/python3.10/site-packages/mesonbuild/backend/ninjabackend.py", line 548, in generate
self.generate_tests()
File "/usr/lib/python3.10/site-packages/mesonbuild/backend/ninjabackend.py", line 1093, in generate_tests
self.serialize_tests()
File "/usr/lib/python3.10/site-packages/mesonbuild/backend/backends.py", line 567, in serialize_tests
self.write_test_file(datafile)
File "/usr/lib/python3.10/site-packages/mesonbuild/backend/backends.py", line 943, in write_test_file
self.write_test_serialisation(self.build.get_tests(), datafile)
File "/usr/lib/python3.10/site-packages/mesonbuild/backend/backends.py", line 1017, in write_test_serialisation
pickle.dump(self.create_test_serialisation(tests), datafile)
File "/usr/lib/python3.10/site-packages/mesonbuild/backend/backends.py", line 1002, in create_test_serialisation
cmd_args.append(self.construct_target_rel_path(a, t.workdir))
File "/usr/lib/python3.10/site-packages/mesonbuild/backend/backends.py", line 1021, in construct_target_rel_path
return self.get_target_filename(a)
File "/usr/lib/python3.10/site-packages/mesonbuild/backend/backends.py", line 253, in get_target_filename
assert(isinstance(t, build.BuildTarget))