Fix unused_parens when cast is followed LT

tests/ui/lint/unused/issue-117142-invalid-remove-parens.rs

@@ -0,0 +1,19 @@
+// check-pass
+#![warn(unused_parens)]
+
+fn main() {
+    let a: i32 = 1;
+    let b: i64 = 1;
+
+    if b + a as (i64) < 0 {
+        println!(":D");
+    }
+    if b + b + a as (i64) < 0 {
+        println!(":D");
+    }
+    let c = a + b as (i32) < 0;
+    let mut x = false;
+    x |= false || (b as (i32) < 0);
+
+    let d = 1 + 2 + 3 * 4 as (i32) < 10;
+}