Summary
WT-8989 introduces column groups and indexes into "test_tiered02.py". But the test crashes when "ds.populate()" is called with an opened cursor. If I call "cursor.close()" right before populating the dataset the crash is not observed anymore.

To reproduce the issue, just u_ncomment the line under "FIXME: WT-9001" comment._

Here's the crash signature:

AssertionError: unexpected error output, contains: "[1648180962:827319][17388:0x7f6790703740], test_tiered02.test_tiered02.test_tiered(dirstore.complex_ds), WT_SESSION.create: [WT_VERB_DEFAULT][ERROR]: __create_colgroup, 396: Can't create 'colgroup:test_tiered02:cgroup1' for non-existent table 'test_tiered02': Device or resource busy

Acceptance Criteria (Definition of Done)
The test should work with SimpleDataset and ComplexDataset without any crashes.