glib/tests/gdatetime.c: Fix TZ envvar test on Windows

Windows does not recognize the "America/Recife" as a valid timezone
identifier, so setting the TZ envvar to that will result "UTC" to be
returned on Windows.

Instead, set TZ to be the Windows equivilant "SA Eastern Standard
Time", and see whether that is indeed our identifier when we create the
GTimeZone using that.
diff --git a/glib/tests/gdatetime.c b/glib/tests/gdatetime.c
index 4e6559a..c805a8e 100644
--- a/glib/tests/gdatetime.c
+++ b/glib/tests/gdatetime.c
@@ -2441,12 +2441,21 @@
   g_time_zone_unref (tz);
 
   /* Local timezone tests. */
+#ifdef G_OS_WIN32
+  if (g_setenv ("TZ", "SA Eastern Standard Time", TRUE))
+    {
+      tz = g_time_zone_new_local ();
+      g_assert_cmpstr (g_time_zone_get_identifier (tz), ==, "SA Eastern Standard Time");
+      g_time_zone_unref (tz);
+    }
+#else
   if (g_setenv ("TZ", "America/Recife", TRUE))
     {
       tz = g_time_zone_new_local ();
       g_assert_cmpstr (g_time_zone_get_identifier (tz), ==, "America/Recife");
       g_time_zone_unref (tz);
     }
+#endif
 
   if (g_setenv ("TZ", "some rubbish", TRUE))
     {