fix mangled string

Author: sjrd

compiler/src/dotty/tools/backend/sjs/JSEncoding.scala

@@ -206,7 +206,7 @@ object JSEncoding {
        */
       ir.Definitions.BoxedUnitClass
     } else {
-      ir.Definitions.encodeClassName(sym.fullName.toString)
+      ir.Definitions.encodeClassName(fullyMangledString(sym.fullName))
     }
   }
 
@@ -231,7 +231,7 @@ object JSEncoding {
         val c = base.charAt(i)
         if (c == '_')
           result.append("$und")
-        else if (Character.isJavaIdentifierPart(c))
+        else if (Character.isJavaIdentifierPart(c) || c == '.')
           result.append(c)
         else
           result.append("$u%04x".format(c.toInt))