test_sequential: resolve() the system_executable (#2751)

When the _base_executable is a hardlink (macOS homebrew), then the
virtualenv `PythonInfo.current_system()` call might not return the same
path as tox's PythonInfo.interpreter, even though they would be pointing
to the same file.

fix issue #2720

Author: masenf

docs/changelog/2720.bugfix.rst

@@ -0,0 +1,2 @@
+Fix assertion in ``test_result_json_sequential`` when interpreter
+``_base_executable`` is a hardlink (macOS homebrew) - by user:`masenf`

tests/session/cmd/test_sequential.py

@@ -70,7 +70,7 @@ def test_result_json_sequential(
 
     py_info = PythonInfo.current_system()
     host_python = {
-        "executable": py_info.system_executable,
+        "executable": str(Path(py_info.system_executable).resolve()),
         "extra_version_info": None,
         "implementation": py_info.implementation,
         "is_64": py_info.architecture == 64,