- `const` without value
- `delete` of expression
- redefining `arguments` or `eval`
extend `test/ufuzz.js`
- optionally generate "use strict"
- improve handling of test cases with syntax errors
- group IIFE generation
- generate bare anonymous functions
- workaround `console.log()` for `new function()`
- generate expressions with `this`
fixes#1810
