JDK-8351997 shows there is a gap in current configuration coverage with jcstress. When split compilation is enabled, harness asks to int/C1/C2 each actor method separately. Unfortunately, there are cases in Hotspot where the barrier scheme depends on whether C2 is globally enabled. JDK-8351997 would fail split int/C1 test with C2 globally disabled.

Therefore, harness should run with global int/C1/C2 modes even with split compilation. This complicates testing matrix quite a bit, but it should capture bugs like JDK-8351997 more reliably.