tests: prune skips

[detule]

I am seeing this in our pipelines:

────────────────────────────────────────────────────────────────────────────────
Warning ('test-driver-sqlite.R:50:3'): SQLite
Unused skip expressions: create_temporary_table
Backtrace:
    ▆
 1. └─DBItest::test_sql(...) at test-driver-sqlite.R:50:3
 2.   └─DBItest:::run_tests(ctx, spec_sql, skip, run_only, test_suite) at DBItest/R/test-sql.R:17:3
 3.     └─DBItest:::get_skip_names(skip) at DBItest/R/run.R:29:3
────────────────────────────────────────────────────────────────────────────────

Looks like perhaps this test was removed from the testing suite.