Use <support/test-driver.c> in stdlib/tst-strtod-overflow.c

This downstream-only patch is needed because test-skeleton.c contains
a copy of the old test skeleton (unlike upstream), resulting in the
following error:

In file included from tst-strtod-overflow.c:53:0:
../test-skeleton.c:65:20: error: static declaration of 'test_dir' follows non-static declaration
 static const char *test_dir;
                    ^
In file included from tst-strtod-overflow.c:23:0:
../support/test-driver.h:65:20: note: previous declaration of 'test_dir' was here
 extern const char *test_dir;
                    ^

diff --git a/stdlib/tst-strtod-overflow.c b/stdlib/tst-strtod-overflow.c
index fd1be79f3f58c64b..2b30947d9a9fa03a 100644
--- a/stdlib/tst-strtod-overflow.c
+++ b/stdlib/tst-strtod-overflow.c
@@ -48,6 +48,4 @@ do_test (void)
   return 0;
 }
 
-#define TEST_FUNCTION do_test ()
-#define TIMEOUT 5
-#include "../test-skeleton.c"
+#include <support/test-driver.c>