Temporarily remove isInitialized and tests, but keep the implementation

This is needed because we want the compiler code to stay as much the
same in master and in 1.2 as possible

compiler/testData/codegen/box/properties/lateinit/isInitializedAndDeinitialize/topLevelProperty.kt

@@ -1,12 +0,0 @@
-// TARGET_BACKEND: JVM
-// LANGUAGE_VERSION: 1.2
-// WITH_RUNTIME
-
-lateinit var bar: String
-
-fun box(): String {
-    if (::bar.isInitialized) return "Fail 1"
-    bar = "OK"
-    if (!::bar.isInitialized) return "Fail 2"
-    return bar
-}