libshiboken: Fix crashes with static strings in Python 3.11

libshiboken: Fix crashes with static strings in Python 3.11

In Python 3.11, some strings come with a refcount above decimal
1000000000, apparently indicating that they are interned. Replace the
mechanism by PyUnicode_InternFromString().

Task-number: PYSIDE-1960
Pick-to: 6.3 6.2 5.15
Change-Id: I6436afee351f89da5814b5d6bc76970b1b508168
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Christian Tismer <tismer@stackless.com>
(cherry picked from commit a09a1db8391243e6bb290ee66bb6e3afbb114c61)

Gbp-Pq: Name libshiboken-Fix-crashes-with-static-strings-in-Python-3.11.patch