[V8] Add support for MinGW-w64

[V8] Add support for MinGW-w64

This includes several upstream patches to allow V8 to work properly
with MinGW-w64.

Upstream patches:
- https://chromiumcodereview.appspot.com/9959050
- https://chromiumcodereview.appspot.com/10103030
- https://chromiumcodereview.appspot.com/10019012
- https://chromiumcodereview.appspot.com/10108022
- https://chromiumcodereview.appspot.com/10116001

Change-Id: I86876aa67a5bdea1208c7ee33a739eb7c00fd72b
Reviewed-by: Peter Varga <pvarga@inf.u-szeged.hu>
Reviewed-by: Kent Hansen <kent.hansen@nokia.com>