Introduce record_testsuite_property fixture

This exposes the functionality introduced in fa6acdc as a session-scoped fixture.

Plugins that want to remain compatible with the `xunit2`
standard should use this fixture instead of `record_property`.

Fix #5202

doc/en/reference.rst

@@ -424,6 +424,14 @@ record_property
 
 .. autofunction:: _pytest.junitxml.record_property()
 
+
+record_testsuite_property
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+**Tutorial**: :ref:`record_testsuite_property example`.
+
+.. autofunction:: _pytest.junitxml.record_testsuite_property()
+
 caplog
 ~~~~~~