Revert "Missing tautological compare warnings due to unary operators"

This reverts commit 0cc3c184.

The changes did not account for templated code where one instantiation
may trigger the diagnostic but other instantiations will not, as in:
```
template <int I, class T>
void foo(int x) {
    bool b1 = (x & sizeof(T)) == 8;
    bool b2 = (x & I) == 8;
    bool b3 = (x & 4) == 8;
}

void run(int x) {
    foo<4, int>(8);
}
```