An IfInstruction tests its condition for non-zero, so a bool-typed
`if (c) ldc.i4 1 else ldc.i4 0` always equals `c != 0`, which
ExpressionTransforms already folds to `c` for bool `c`. Without this
identity the node reached the C# output as `c ? true : false`, or as
`c || 1 == 0` once negated. The lost `??` form is not addressed here.
dualfroz
upstream