* install a widestring manager on the WASI platform in testrunner.rtlobjpas.pp

packages/rtl-objpas/tests/testrunner.rtlobjpas.pp

@@ -32,6 +32,9 @@ uses
   cthreads,
   cwstring,
 {$endif}
+{$ifdef wasi}
+  unicodeducet, fpwidestring,
+{$endif}
 {$ifdef useffi}
   ffi.manager,
 {$endif}