Add missing directory to clean_all.sh

Author: bjorn3

clean_all.sh

@@ -1,5 +1,5 @@
 #!/bin/bash --verbose
 set -e
 
-rm -rf target/ build/ build_sysroot/{sysroot_src/,target/} perf.data{,.old}
+rm -rf target/ build/ build_sysroot/{sysroot_src/,target/,compiler-builtins/} perf.data{,.old}
 rm -rf rand/ regex/ simple-raytracer/