scripts/test.py: improve --cibw-release-2.

Need to restrict linuxaarch testing to python-3.9 and python-3.13, otherwise it
times-out on github.

Author: julian-smith-artifex-com

scripts/test.py

@@ -346,6 +346,9 @@ def main(argv):
 
         elif arg == '--cibw-release-2':
             env_extra['CIBW_ARCHS_LINUX'] = 'aarch64'
+            # Testing only first and last python versions because otherwise
+            # Github times out after 6h.
+            env_extra['CIBW_BUILD'] = 'cp39* cp313*'
             os_names = ['linux']
 
         elif arg == '--cibw-archs-linux':