Avoid recreation of virtualenv due to symlinks

If people called tox alternating between `python3 -m tox` and `tox`,
they would endup triggering venv recreation, even if there was only
one python. We should always resolve symlinks to avoid such false
env invalidations.

docs/changelog/2574.bugfix.rst

@@ -0,0 +1 @@
+Resolve symlinks when saving Python executable path - by :user:`ssbarnea`.

src/tox/tox_env/python/virtual_env/api.py

@@ -140,7 +140,7 @@ def _get_python(self, base_python: list[str]) -> PythonInfo | None:  # noqa: U10
             version=interpreter.version,
             is_64=(interpreter.architecture == 64),
             platform=interpreter.platform,
-            extra={"executable": Path(interpreter.system_executable)},
+            extra={"executable": Path(interpreter.system_executable).resolve()},
         )
 
     def prepend_env_var_path(self) -> list[Path]: