Tests that the DFG doesn't crash if we constant fold the first read of a local variable in a block that is the result of merging two blocks, where the first doesn't touch the local and the second reads it.

On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".


PASS bar(5) is 42 on all iterations including after DFG tier-up.
PASS successfullyParsed is true

TEST COMPLETE