prebuilts: Update xz to non-broken version

 * The aosp prebuilt does not work for kernel builds that use BCJ
   compression options. It errors out with the below message:
   - xz: Unsupported filter chain or filter options
 * Now that we are forced on R to use the prebuilt, let's use a
   functional one

* Source version: xz-5.2.5
* Configure options (Linux):
  - CFLAGS="-O2 -fPIC" CXXFLAGS="-O2 -fPIC" \
    ./configure --disable-shared --enable-static --disable-rpath
* Configure options (macOS):
  - CFLAGS="-O2 -fPIC" CXXFLAGS="-O2 -fPIC" \
    ./configure --disable-rpath
 * This is due to the fact that macOS doesn't support static
   compilation.

Change-Id: Ide9b97daba84c9fcc4e2306a9e03f1b2c3a4037a
2 files changed