Fix: Android JavaScriptCore does not work on pre-4.4 OS's due to less stack memory

maxPerThreadStackUsage=1MB still crashes on pre-4.4 device in some cases. Finally I was able to pass all of testapi API unit tests by following options on my 4.4 and 4.2 devices. But I'm not quite sure how and why it works.

```c++
#define JSC_OPTIONS(v) \
...
    v(unsigned, maxPerThreadStackUsage, 4 * MB) \
    v(unsigned, reservedZoneSize, 64 * KB) \
```
Merge pull request #30 from infosia/javascriptcore-android

Merged.