Add tests for duplicated attributes on expressions(rust-lang#4452)

Author: chansuke

tests/source/issue-4452.rs

@@ -0,0 +1,15 @@
+fn a(&self) -> i64 {
+    #[allow(clippy::cast_possible_wrap)]
+    1u64 as i64
+}
+
+fn b(&self) -> i64 {
+    #[allow(clippy::cast_possible_wrap)]
+    #[attr]
+    1..2
+}
+
+fn foo() {
+    #[allow(clippy::cast_possible_wrap)]
+    {}
+}

tests/target/issue-4452.rs

@@ -0,0 +1,15 @@
+fn a(&self) -> i64 {
+    #[allow(clippy::cast_possible_wrap)]
+    1u64 as i64
+}
+
+fn b(&self) -> i64 {
+    #[allow(clippy::cast_possible_wrap)]
+    #[attr]
+    1..2
+}
+
+fn foo() {
+    #[allow(clippy::cast_possible_wrap)]
+    {}
+}