Skip running FSM workloads that use the compact command on the LSM build variant

WT-2523 is a known hang when running the "compact" command. We should skip running the compact.js and the compact_simultaneous_padding_bytes.js FSM workloads when using WiredTiger's LSM trees.

We should disable these tests in a way that doesn't cause us to lose coverage of running the "compact" command concurrently with other operations on other storage engines. One option is to use db[this.threadCollName].stats().wiredTiger.type === "lsm" to further refine the existing storage engine checks and skip running the "compact" command altogether.