Remove unnecessary #include <limits.h>

This include was probably copied from tuplestore.c, but it's not needed.

Extracted from a larger patch submitted by vignesh C <vignesh21@gmail.com>

Discussion: https://postgr.es/m/CALDaNm1B9naPDTm3ox1m_yZvOm3KA5S4kZQSWWAeLHAQ=3gV1Q@mail.gmail.com

Author: alvherre

src/backend/utils/sort/sharedtuplestore.c

@@ -29,8 +29,6 @@
 #include "storage/sharedfileset.h"
 #include "utils/sharedtuplestore.h"
 
-#include <limits.h>
-
 /*
  * The size of chunks, in pages.  This is somewhat arbitrarily set to match
  * the size of HASH_CHUNK, so that Parallel Hash obtains new chunks of tuples