[3.11] gh-109615: Fix support test_copy_python_src_ignore() (#109958) (#109962)

gh-109615: Fix support test_copy_python_src_ignore() (#109958)

Fix the test when run on an installed Python: use "abs_srcdir" of
sysconfig, and skip the test if the Python source code cannot be
found.

* Tools/patchcheck/patchcheck.py, Tools/freeze/test/freeze.py and
  Lib/test/libregrtest/utils.py now first try to get "abs_srcdir"
  from sysconfig, before getting "srcdir" from sysconfig.
* test.pythoninfo logs sysconfig "abs_srcdir".

(cherry picked from commit b89ed9df39)

Lib/test/pythoninfo.py

@@ -524,7 +524,10 @@ def collect_sysconfig(info_add):
         'Py_NOGIL',
         'SHELL',
         'SOABI',
+        'abs_builddir',
+        'abs_srcdir',
         'prefix',
+        'srcdir',
     ):
         value = sysconfig.get_config_var(name)
         if name == 'ANDROID_API_LEVEL' and not value: