Switch to the new stdlib source generation scheme

Remove old generated sources for stdlib-jvm and stdlib-js

libraries/stdlib/jvm/src/generated/_StringsJvm.kt

@@ -0,0 +1,22 @@
+@file:kotlin.jvm.JvmMultifileClass
+@file:kotlin.jvm.JvmName("StringsKt")
+@file:kotlin.jvm.JvmVersion
+
+package kotlin.text
+
+//
+// NOTE THIS FILE IS AUTO-GENERATED by the GenerateStandardLib.kt
+// See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
+//
+
+import kotlin.*
+import kotlin.text.*
+import kotlin.comparisons.*
+
+/**
+ * Returns a [SortedSet][java.util.SortedSet] of all characters.
+ */
+public fun CharSequence.toSortedSet(): java.util.SortedSet<Char> {
+    return toCollection(java.util.TreeSet<Char>())
+}
+