[TargetLowering] Add getBooleanContents contents check to "SETCC (SETCC),...

[TargetLowering] Add getBooleanContents contents check to "SETCC (SETCC), [0|1], [EQ|NE]  -> SETCC" combine.

This combine is only valid if the inner setcc produces a 0/1 result
or the inner type is MVT::i1.

I haven't seen this cause any issues, just happened to notice it
while reviewing combines in this function.

While there also fix another call to use the value type from the
SDValue for the operand instead of calling SDNode::getValueType(0).
Though its likely the use is result 0, its not guaranteed.