ci: run test_fstring on wasm-wasi (#8832)

- Add test_fstring to the wasm-wasi test list.
- Expect test_global to fail when unittest is frozen

Assisted-by: Claude Code:claude-sonnet-5

Signed-off-by: Jiwoo Ahn <ikwydls1314@gmail.com>

.github/workflows/ci.yaml

@@ -1007,6 +1007,7 @@ jobs:
         test_class
         test_genericpath
         test_grammar
+        test_fstring
     steps:
       - name: Skip wasm-wasi when rust sources did not change
         if: env.RUN_WASM_WASI != 'true'