Don't output test artifacts into working directory

Author: compiler-errors

.gitignore

@@ -50,7 +50,6 @@ build/
 /target
 /src/bootstrap/target
 /src/tools/x/target
-/inc-fat/
 # Created by default with `src/ci/docker/run.sh`
 /obj/
 /rustc-ice*

tests/ui/lto/debuginfo-lto-alloc.rs

@@ -9,7 +9,8 @@
 // that compilation is successful.
 
 //@ check-pass
-//@ compile-flags: --test -C debuginfo=2 -C lto=fat -C incremental=inc-fat
+//@ compile-flags: --test -C debuginfo=2 -C lto=fat
+//@ incremental
 
 extern crate alloc;