Update mingw prebuilt to ab/12895535

Replace the content of the directory with the
x86_64-w64-mingw32-linux-x86_64.tar.bz2 artifact, then massage the
results:

 - Avoid deleting existing files, like:
    - .gitignore
    - Android.bp
    - METADATA
    - OWNERS
    - build-mingw32-toolchain.sh
    - licenses/ directory
    - toolchain-patches/ directory
    - x86_64-w64-mingw32/lib/libWinHvEmulation.a and
      x86_64-w64-mingw32/lib/libWinHvPlatform.a libraries aren't
      part of a new mingw artifact, but keep them in this prebuilt
      project.

 - Avoid adding new files in these directories:
    - bin/*
    - x86_64-w64-mingw32/bin/*
   The x86_64-w64-ming32/bin/libwinpthread-1.dll is updated, however.

Bug: http://b/388603030
Test: treehugger
Change-Id: I650f80c198bced5e0087e122c789a836f02a6450

1284 files changed