[JS FE] Prohibit external inline classes

#KT-26138 Fixed

compiler/testData/diagnostics/testsWithJsStdLib/native/inlineClass.kt

@@ -0,0 +1,9 @@
+// !LANGUAGE: +InlineClasses
+
+external inline class <!WRONG_EXTERNAL_DECLARATION!>C(<!EXTERNAL_CLASS_CONSTRUCTOR_PROPERTY_PARAMETER!>val a: Int<!>)<!> {
+    fun foo()
+}
+
+<!WRONG_MODIFIER_TARGET!>inline<!> external enum class <!WRONG_EXTERNAL_DECLARATION!>E<!> {
+    A
+}