Closes #96612

@dotnet/jit-contrib It seems that in lower we have a worrisome pattern to handle nodes like this:

// Returns:
//     A pointer to the next node to evaluate. On no operation, returns nullptr.
//
GenTree* LowerFoo(GenTree* tree)
{
    if (!someValidation)
        return nullptr;

    return newNode->gtNext;
}

and then caller assumes that nullptr means nothing was handled. Which is not true - it could be handled and it's just that gtNext is nullptr.

This is exactly what happens with #96612
TryLowerAndOrToCCMP converts a binary op to GT_SECC and returns nullptr and then ContainBinaryNode fails because node is no longer a simple op.

The correct pattern should be

bool TryLowerFoo(GenTree* node, GenTree** next)
{
    if (!someValidation)
        return false;

    *next = newNode->gtNext;
    return true;
}

I'll inspect more functions for this pattern separately.