-Wconstant-logical-operand should not fire for expressions involving macros

[AaronBallman]

Clang currently issues this diagnostic when the constant in question is a macro, as in (live example):

#ifndef X
#define X 0
#endif

#ifndef Y
#define Y 2
#endif

bool foo() {
  return X || Y;
}

I think any use of a macro should suppress the diagnostic on the assumption that the macro value is constant for one configuration but may not be constant in all configurations. However, I can also see why we might want to still diagnose macro uses, such as cases like:

void func(int error) {
  if (ENOMEM || error == 12)
    ...
}

where the user could have forgotten to add error == to the expression. So it might be that we want to split this off into separate diagnostic groups.

Relates to discussion in https://reviews.llvm.org/D142609