igt@gem_exec_reuse@(baggage|contexts) are slow to agonizingly slow on all platforms
These tests are responsible for a significant amount of the overall reported time of a CI FULL run:
- shard-skl: 2% (~5 minutes)
- shard-kbl: 1% (~1.5 minutes)
- shard-apl: 1.7% (~3 minutes)
- shard-glk: 1% (2.5 minutes)
- shard-icl: 0.5% (1 minute)
- shard-tgl: 0.5% (1 minute)