[SimplifyCFG] Create logical or in SimplifyCondBranchToCondBranch()

[SimplifyCFG] Create logical or in SimplifyCondBranchToCondBranch()

We need to use a logical or instead of a bitwise or to preserve
poison behavior. Poison from the second condition should not
propagate if the first condition is true.

We were already handling this correctly in FoldBranchToCommonDest(),
but not in this fold. (There are still other folds with this issue.)