These conversions do not necessarily improve readability. They are
converted in this commit so that the lint is free to find new instances.

Conversion of functions of the form:

     bool check() {
          if (cond1) {
               return false;
          }
          if (cond2) {
               return false;
          }
          return true;
     }

are not necessarily better as:

     bool check() {
          return !cond1 && !cond2;
     }

since there may be other checks to add in the future or existing checks
might have more context around them. This usually occurs in validation
or dirty check functions.