anchor.diff:      emitBraceWrapped(emitStatementsClosure);
       emit(' catch (exception, stackTrace) ', newline: false);
       emitBraceWrapped(emitStatementsClosure);
  -    if (rollDice(2)) {
  +    if (coinFlip()) {
         emit(' finally ', newline: false);
         emitBraceWrapped(emitStatementsClosure);
       }
  
positive.code:   // Expressions.
    //
  
    // TODO(bkonyi): swap to use coinFlip()
    void emitBool() => emit(rollDice(2) ? 'true' : 'false');
  
    void emitSmallPositiveInt({int limit = 50, bool includeSemicolon = false}) {
      emit('${choose(limit)}');
  
negative.code:           currentClass = null;
          }
        }
        if (coinFlip() || classParents.length > parentClass) {
          break;
        } else {
          parentClass = classParents[parentClass];
  