stage2: Change optional non-null field to i8

This is a workaround for https://github.com/llvm/llvm-project/issues/56585
which causes writes to i1 in memory to be optimized to an incorrect value.
Unfortunately, this does not save users from running into this bug with u1
in their own types.

However, this does seem to be enough to get the behavior tests working.
This resolves #11450 on my machine.
b93a38860dCody Tapscott committed on 7/19/2022, 5:33:41 PM· committed by Andrew Kelleyparent0e26c61
1 file changedLine totals unavailable