check.h: remove obsolete header

Since we switched from autotools to Meson in commit
94592c1406, we don't need to include
`config.h` early to properly enable large file support.  Meson passes
the required macros on the compiler command line instead of defining
them in `config.h`.

This means we can include `config.h` at any time, whenever we want to
check its macros, and there are no ordering constraints.

src/util/LazyRandomEngine.cxx

@@ -17,7 +17,6 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#include "config.h"
 #include "LazyRandomEngine.hxx"
 
 void

src/util/LazyRandomEngine.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_LAZY_RANDOM_ENGINE_HXX
 #define MPD_LAZY_RANDOM_ENGINE_HXX
 
-#include "check.h"
-
 #include <random>
 
 #include <assert.h>

src/util/Tokenizer.cxx

@@ -27,7 +27,6 @@
  * OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include "config.h"
 #include "Tokenizer.hxx"
 #include "CharUtil.hxx"
 #include "StringStrip.hxx"