Delete unused mingw bins am: 5f7f053b5f am: 82d8129b86

Original change: https://android-review.googlesource.com/c/platform/prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8/+/1886652

Change-Id: I79d908d3054694516d5e0f86b997fa52ee5f8e67