Dumper.xs: Port ESC_NATIVE back on EBCDIC

Wrap its definition with LATIN1_TO_NATIVE() which will automatically
port it back as far as possible.

This is the only use of ESC_NATIVE on cpan, so I don't think it's worth
putting it in ppport.h

dist/Data-Dumper/Dumper.xs

@@ -22,7 +22,7 @@
  * calling this .xs file for releases where they aren't defined */
 
 #ifndef ESC_NATIVE          /* \e */
-#   define ESC_NATIVE 27
+#   define ESC_NATIVE LATIN1_TO_NATIVE(27)
 #endif
 
 /* SvPVCLEAR only from perl 5.25.6 */