[3.12] gh-114275: Skip doctests that use asyncio in test_pdb for WASI builds (GH-114309) (#114439)

gh-114275: Skip doctests that use `asyncio` in `test_pdb` for WASI builds (GH-114309)
(cherry picked from commit efb81a6)

Co-authored-by: Nikita Sobolev <[email protected]>

Author: miss-islington