Cleanup: post-cleanup after deprecation cleanup in compiler

Replace `takeIf { !expr }` with `takeUnless { expr }`.
Cleanup redundant parethesis as in `listOf((expr))`.
Replace `listOf(expr)` with `expr.let(::listOf)` where the former caused significant indentation change.

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/EnumClassLowering.kt

@@ -167,8 +167,8 @@ class EnumClassLowering(val context: JvmBackendContext) : ClassLoweringPass {
         private fun lowerEnumEntries() {
             irClass.declarations.transformFlat { declaration ->
                 if (declaration is IrEnumEntry) {
-                    listOf(createFieldForEnumEntry(declaration)) +
-                    listOfNotNull(lowerEnumEntryClass(declaration.correspondingClass))
+                    listOfNotNull(createFieldForEnumEntry(declaration),
+                                  lowerEnumEntryClass(declaration.correspondingClass))
                 }
                 else null
             }