Move sysroots into subdirectory am: 4cd39c7c1e am: 51914db19a am: 427c538442

Original change: https://android-review.googlesource.com/c/platform/prebuilts/build-tools/+/1989151

Change-Id: I9b9a34bcec1c5604e74d0d1142e295bfd61b467e