Extracted 'deparenthesizeArgument', used it where necessary

#KT-6176 Fixed

compiler/testData/diagnostics/tests/functionLiterals/functionLiteralInIf.kt

@@ -0,0 +1,15 @@
+// !DIAGNOSTICS: -UNUSED_VARIABLE -UNUSED_EXPRESSION
+
+import java.util.HashSet
+
+fun test123() {
+    val g: (Int) -> Unit = if (true) {
+        val set = HashSet<Int>();
+        { i ->
+            set.add(i)
+        }
+    }
+    else {
+        { it -> it }
+    }
+}