Don't reduce test timeout to less than default

This removes all overrides of TIMEOUT that are less than or equal to the
default timeout.

crypt/sha256c-test.c

@@ -57,6 +57,5 @@ do_test (void)
   return result;
 }
 
-#define TIMEOUT 6
 #define TEST_FUNCTION do_test ()
 #include "../test-skeleton.c"