Fixed an ES5 strict test that crashes in Chrome

The test `(function f() { f = 123; })()` actually throws a SyntaxError on evaluation (`SyntaxError: Assignment to constant variable`), not a TypeError on execution, in the current Chrome. I'm really not sure which is fully correct for either the ES5 or ES6 specs. Nevertheless, I've changed that line to be `eval`ed so that the entire script doesn't crash.

Also, the link to the strict mode page on the ES5 test page is fixed.