Make inline class wrapper constructor private

compiler/testData/codegen/bytecodeListing/inlineClasses/computablePropertiesInsideInlineClass.txt

@@ -1,7 +1,7 @@
 @kotlin.Metadata
 public final class Foo {
     private final field x: int
-    public synthetic method <init>(p0: int): void
+    private synthetic method <init>(p0: int): void
     public final static @org.jetbrains.annotations.NotNull method box(p0: int): Foo
     public static method constructor(p0: int): int
     public static method equals(p0: int, @org.jetbrains.annotations.Nullable p1: java.lang.Object): boolean