Add if statement to only use sys.last_exc in versions >= 3.12.0

AUTHORS

@@ -127,6 +127,7 @@ Edison Gustavo Muenz
 Edoardo Batini
 Edson Tadeu M. Manoel
 Eduardo Schettino
+Edward Haigh
 Eli Boyarski
 Elizaveta Shashkova
 Éloi Rivard

src/_pytest/runner.py

@@ -168,6 +168,7 @@ def pytest_runtest_call(item: Item) -> None:
         del sys.last_type
         del sys.last_value
         del sys.last_traceback
+        if sys.version_info >= (3,12,0):
             del sys.last_exc
     except AttributeError:
         pass
@@ -177,6 +178,7 @@ def pytest_runtest_call(item: Item) -> None:
         # Store trace info to allow postmortem debugging
         sys.last_type = type(e)
         sys.last_value = e
+        if sys.version_info >= (3,12,0):
             sys.last_exc = e
         assert e.__traceback__ is not None
         # Skip *this* frame