Drop deprecated Synchronized, Volatile annotations and synchronized fun

(cherry picked from commit b138579e34de62e63ad9e3f2a6bf8eed22f5f9bd)

runtime/src/main/kotlin/kotlin/native/Compatibility.kt

@@ -1,29 +0,0 @@
-/*
- * 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 file.
- */
-
-package kotlin
-
-// Note:
-// Right now we don't want to have neither 'volatile' nor 'synchronized' at runtime, as it has different
-// concurrency approach.
-
-@Target(AnnotationTarget.PROPERTY, AnnotationTarget.FIELD)
-@Retention(AnnotationRetention.SOURCE)
-@Deprecated("Do not use Volatile annotation in pure Kotlin/Native code", level = DeprecationLevel.ERROR)
-public annotation class Volatile
-
-@Target(AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY_GETTER, AnnotationTarget.PROPERTY_SETTER)
-@Retention(AnnotationRetention.SOURCE)
-@Deprecated("Do not use Synchronized annotation in pure Kotlin/Native code", level = DeprecationLevel.ERROR)
-public annotation class Synchronized
-
-/**
- * An actual implementation of `synchronized` method. This method is not supported in Kotlin/Native
- * @throws UnsupportedOperationException always
- */
-@kotlin.internal.InlineOnly
-@Deprecated("Do not use 'synchronized' function in Kotlin/Native code", level = DeprecationLevel.ERROR)
-public actual inline fun <R> synchronized(@Suppress("UNUSED_PARAMETER") lock: Any, block: () -> R): R =
-        throw UnsupportedOperationException("synchronized() is unsupported")