String.compareTo: SinceKotlin in JS and common, restore default parameter value in JVM

Default parameter is required to generate docs with Dokka for now.

#KT-18067

libraries/stdlib/common/src/kotlin/TextH.kt

@@ -158,6 +158,13 @@ expect fun String.replaceFirst(oldValue: String, newValue: String, ignoreCase: B
  */
 expect fun String?.equals(other: String?, ignoreCase: Boolean = false): Boolean
 
+/**
+ * Compares two strings lexicographically, optionally ignoring case differences.
+ */
+@SinceKotlin("1.2")
+expect fun String.compareTo(other: String, ignoreCase: Boolean = false): Int
+
+
 // From stringsCode.kt
 
 internal inline expect fun String.nativeIndexOf(ch: Char, fromIndex: Int): Int
@@ -290,11 +297,6 @@ expect fun Int.toString(radix: Int): String
 @SinceKotlin("1.2")
 expect fun Long.toString(radix: Int): String
 
-/**
- * Compares two strings lexicographically, optionally ignoring case differences.
- */
-expect fun String.compareTo(other: String, ignoreCase: Boolean = false): Int
-
 @PublishedApi
 internal expect fun checkRadix(radix: Int): Int
 

libraries/stdlib/js/src/kotlin/string.kt

@@ -74,7 +74,9 @@ public inline val CharSequence.size: Int get() = length
 @kotlin.internal.InlineOnly
 internal inline fun String.nativeReplace(pattern: RegExp, replacement: String): String = asDynamic().replace(pattern, replacement)
 
-public actual fun String.compareTo(other: String, ignoreCase: Boolean): Int {
+@SinceKotlin("1.2")
+@Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
+public actual fun String.compareTo(other: String, ignoreCase: Boolean = false): Int {
     if (ignoreCase) {
         val n1 = this.length
         val n2 = other.length

libraries/stdlib/jvm/src/kotlin/text/StringsJVM.kt

@@ -317,7 +317,8 @@ public inline fun String.codePointCount(beginIndex: Int, endIndex: Int): Int =
 /**
  * Compares two strings lexicographically, optionally ignoring case differences.
  */
-public actual fun String.compareTo(other: String, ignoreCase: Boolean): Int {
+@Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
+public actual fun String.compareTo(other: String, ignoreCase: Boolean = false): Int {
     if (ignoreCase)
         return (this as java.lang.String).compareToIgnoreCase(other)
     else