Implement String to/from ByteArray conversion (KT-24810)

libraries/stdlib/jvm/test/testUtilsJVM.kt

@@ -16,3 +16,12 @@ private val isJava6 = System.getProperty("java.version").startsWith("1.6.")
 internal actual fun String.removeLeadingPlusOnJava6(): String =
     if (isJava6) removePrefix("+") else this
 
+private val isJava7 = System.getProperty("java.version").startsWith("1.7.")
+
+private val isJava8AndAbove = !isJava6 && !isJava7
+
+internal actual inline fun testOnNonJvm6And7(f: () -> Unit) {
+    if (isJava8AndAbove) {
+        f()
+    }
+}

libraries/stdlib/jvm/test/text/StringEncodingTestJvm.kt

@@ -0,0 +1,11 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package test.text
+
+
+internal actual val surrogateCodePointDecoding: String = "�"
+
+internal actual val surrogateCharEncoding: ByteArray = byteArrayOf(0x3F)