aconfig: cache.rs: remove unnecessary use statements

Remove unnecessary use from the cache::test module: they already covered
by `use super:*;`.

Bug: 283910447
Test: atest aconfig.test
Change-Id: I9e03385629f38180c0f92080c7f097a8e0d9ef69
diff --git a/tools/aconfig/src/cache.rs b/tools/aconfig/src/cache.rs
index 44ad3dd..972ba41 100644
--- a/tools/aconfig/src/cache.rs
+++ b/tools/aconfig/src/cache.rs
@@ -179,7 +179,6 @@
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::aconfig::{FlagState, Permission};
 
     #[test]
     fn test_add_flag_declaration() {