[Commonizer] Commonize 'val' and 'var' properties

If a setter is not present on all platforms a fallback private setter
shall be emitted.

^KT-47502 Verification Pending
^KT-47691 Verification Pending

native/commonizer/testData/propertyCommonization/setters/commonized/common/package_root.kt

@@ -9,8 +9,16 @@ expect var setterWithDelegation1: Int
 expect var setterWithDelegation2: Int
 
 expect var defaultSetteCustomVisibility1: Int
+expect var defaultSetteCustomVisibility2: Int
+    private set
 expect var defaultSetteCustomVisibility3 = 42
     internal set
+expect var defaultSetteCustomVisibility4: Int
+    private set
+expect var defaultSetteCustomVisibility5: Int
+    private set
 
 expect val propertyWithoutSetter: Int
-expect var propertyWithSetter: Int
+expect var propertyMaybeSetter: Int
+    private set
+expect var propertyWithSetter: Int