Although MCJIT is unsupported, we can and should be running the other
tests. Stacks on top of #124463 (needed to avoid unsupported MCJIT tests
in the top-level test/ExecutionEngine directory running when they
shouldn't).
This effectively reverts b8feeba0b407e703385738af7e415d0c8972a420.
ninja check-llvm-executionengine before:
Total Discovered Tests: 335
Unsupported: 335 (100.00%)
ninja check-llvm-executionengine after:
Total Discovered Tests: 335
Unsupported : 125 (37.31%)
Passed : 209 (62.39%)
Expectedly Failed: 1 (0.30%)
606cf88741