test: fix cache_algorithm_test dev regression failure

[darwin67]

Context

The dev-mode PR regression suite currently runs cache_algorithm_test as split Boost cases. These cases are low-memory cache stress tests, so running them concurrently can over-constrain CI and expose teardown instability:

• cache_algorithm_test::test_index_doesnt_flood_cache_in_small_partition_workload
• cache_algorithm_test::test_index_is_cached_in_big_partition_workload

The failure below happened while both cases were running at the same time.

Observed failure

Run: https://github.com/inngest/ssdb/actions/runs/26522408766/job/78118178061

Failing test:

• boost.cache_algorithm_test.test_index_is_cached_in_big_partition_workload.1

Failure excerpt:

cache_algorithm_test: utils/logalloc.cc:2008: virtual logalloc::region_impl::~region_impl(): Assertion `desc.is_empty()` failed.
Test exited with code -6

Current fix

test/boost/suite.yaml marks cache_algorithm_test as no_parallel_cases, so the binary still runs but its cases execute serially in one test process.

Done when

• The full boost.cache_algorithm_test binary passes in dev CI.
• PR regression CI remains green.