Delete unused mingw bins, leaving windres and windmc am: 1a6340db32 am: 7c727d35e3 am: b8193061e5 am: e7dc0d87e4 am: c80c4481e3

Original change: https://android-review.googlesource.com/c/platform/prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8/+/1867131

Change-Id: Ie7c5c178946eb32ef581f628a9ccfac83b610b4a