Valid ES6 allowJs `error TS8014: 'property declarations' can only be used in a .ts file.`

**TypeScript Version:** 

1.8.2

**Code**

``` ts
// A self-contained demonstration of the problem follows...
class Repro
{
    static property = {
    foo: "bar"
    };
}
```

`tsc --allowJs --out out.js repro.js`

**Expected behavior:**

Compiles without error 

**Actual behavior:** 

```
repro.js(3,5): error TS8014: 'property declarations' can only be used in a .ts file.
```
