Currently, we have some tests, that in slow build variants, are not able to converge because the Balancer is moving data between shards without giving enough time between iterations for operations in the test to complete.

I propose to increase `balancerMigrationsThrottlingMs` to at least 2 seconds only for TSAN build variant builds. If that doesn't resolve the issue, we may want to ban failing tests linked in the BF from the slow variants.