[gobject-introspection] tests: Fix signed-ness of variable

[Philip Chimento <pchimento src gnome org>]

commit f6bcc7d27fa4fb66381564fc4cc839108967e3b0
Author: Philip Chimento <philip endlessm com>
Date:   Sun Mar 11 22:36:51 2018 -0700

    tests: Fix signed-ness of variable
    
    This will otherwise warn.

 tests/gimarshallingtests.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/tests/gimarshallingtests.c b/tests/gimarshallingtests.c
index a231493d..44a4ab30 100644
--- a/tests/gimarshallingtests.c
+++ b/tests/gimarshallingtests.c
@@ -1413,7 +1413,7 @@ gi_marshalling_tests_array_uint64_in (const guint64 *ints, gint length)
 void
 gi_marshalling_tests_array_unichar_in (const gunichar *chars, gint length)
 {
-  unsigned ix;
+  int ix;
   static const gunichar expected[] = GI_MARSHALLING_TESTS_CONSTANT_UCS4;
   g_assert_cmpint (length, ==, 12);
   for (ix = 0; ix < length; ix++)