Remove legacy buildbot scripts

Remove symlinks to scripts that have been renamed in
https://r.android.com/1214056

Test: cd $ANDROID_BUILD_TOP/art && git grep teardown-build
Test: cd $ANDROID_BUILD_TOP/art && git grep symbolize-bui
Test: cd $ANDROID_BUILD_TOP/art && git grep setup-buildbot
Test: cd $ANDROID_BUILD_TOP/art && git grep cleanup-buildbot
Change-Id: Iaccad5fc29742abf843ff66755d7bf5fe5774d70
4 files changed