tdf#97362: TextPortionEnumerationTest partially migrated to python (part 7)

Convert tests:
- test_range2
- test_range3
- test_range4
- test_range5
- test_range6
- test_range7
- test_meta_xchild
- test_meta_xtext
- test_meta_xtextcursor
- test_xtextcursor

Change-Id: Iabfa51869611ee027565102f6658b045a182d66e
Reviewed-on: https://gerrit.libreoffice.org/41589Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>