Fix import resolution getting stuck on nightly

See rust-lang/rust#53481 for details

Author: TedDriggs

derive_builder/tests/builder_name.rs

@@ -19,7 +19,7 @@ fn panic_if_uninitialized() {
 }
 
 #[test]
-fn builder() {
+fn builder_test() {
     let x: Lorem = MyBuilder::default()
         .ipsum("lorem")
         .dolor(Some("dolor"))

derive_builder/tests/custom_default.rs

@@ -51,7 +51,7 @@ mod field_level {
     }
 
     #[test]
-    fn builder() {
+    fn builder_test() {
         let x = LoremBuilder::default()
             .required("ipsum".to_string())
             .explicit_default("lorem".to_string())

derive_builder/tests/lifetime.rs

@@ -15,7 +15,7 @@ fn panic_if_uninitialized() {
 }
 
 #[test]
-fn builder() {
+fn builder_test() {
     let x = LoremBuilder::default().ipsum("ipsum").build().unwrap();
 
     assert_eq!(x, Lorem { ipsum: "ipsum" });