Support correct way of writing/loading version requirement table

Tests are added in subsequent commits.

KT-25120 Fixed

core/metadata/src/org/jetbrains/kotlin/metadata/deserialization/versionSpecificBehavior.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.metadata.deserialization
+
+// The purpose of utilities in this file is to support different behavior in deserialization according to the given binary file's version.
+//
+// For example, if we find a bug in serialization/deserialization and would like to fix it _remaining compatible_ with two latest versions
+// of Kotlin, we can use methods of this class to fix deserialization of the "future" binaries, and later (in the next major version)
+// fix the bug in serialization when the binary version advances to the value supported in the first bug fix.
+
+/**
+ * Before Kotlin 1.4, version requirements for nested classes were deserialized incorrectly: the version requirement table was loaded from
+ * the outermost class and passed to the nested classes and their members, even though indices of their version requirements were pointing
+ * to the other table stored in the nested class (which was not read by deserialization). See KT-25120 for more information
+ */
+fun isVersionRequirementTableWrittenCorrectly(version: BinaryVersion): Boolean =
+    isKotlin1Dot4OrLater(version)
+
+private fun isKotlin1Dot4OrLater(version: BinaryVersion): Boolean {
+    // All metadata versions (JVM, JS, common) will be advanced to 1.4.0 in Kotlin 1.4
+    return version.major == 1 && version.minor >= 4
+}