Trac #33967: sage -t: Print git commit hash and SAGE_LOCAL, SAGE_VENV

`sage -t` already prints the current branch. We add some more
information so that the log files `*test*.log` become more useful.

URL: https://trac.sagemath.org/33967
Reported by: mkoeppe
Ticket author(s): Matthias Koeppe
Reviewer(s): John Palmieri

src/sage/doctest/control.py

@@ -1328,7 +1328,7 @@ def run(self):
             return self.run_val_gdb()
         else:
             self.create_run_id()
-            from sage.env import SAGE_ROOT_GIT
+            from sage.env import SAGE_ROOT_GIT, SAGE_LOCAL, SAGE_VENV
             # SAGE_ROOT_GIT can be None on distributions which typically
             # only have the SAGE_LOCAL install tree but not SAGE_ROOT
             if (SAGE_ROOT_GIT is not None) and os.path.isdir(SAGE_ROOT_GIT):
@@ -1343,6 +1343,18 @@ def run(self):
                     self.log("Git branch: " + branch, end="")
                 except subprocess.CalledProcessError:
                     pass
+                try:
+                    ref = subprocess.check_output(["git",
+                                                      "--git-dir=" + SAGE_ROOT_GIT,
+                                                      "describe",
+                                                      "--always",
+                                                      "--dirty"])
+                    ref = ref.decode('utf-8')
+                    self.log("Git ref: " + ref, end="")
+                except subprocess.CalledProcessError:
+                    pass
+
+            self.log(f"Running with {SAGE_LOCAL=} and {SAGE_VENV=}")
 
             self.log("Using --optional=" + self._optional_tags_string())
             available_software._allow_external = self.options.optional is True or 'external' in self.options.optional