Replace heapam.h includes with {table, relation}.h where applicable.

A lot of files only included heapam.h for relation_open, heap_open etc
- replace the heapam.h include in those files with the narrower
header.

Author: Andres Freund
Discussion: https://postgr.es/m/20190111000539.xbv7s6w7ilcvm7dp@alap3.anarazel.de

src/backend/rewrite/rewriteHandler.c

@@ -20,8 +20,9 @@
  */
 #include "postgres.h"
 
-#include "access/heapam.h"
+#include "access/relation.h"
 #include "access/sysattr.h"
+#include "access/table.h"
 #include "catalog/dependency.h"
 #include "catalog/pg_type.h"
 #include "commands/trigger.h"

src/backend/rewrite/rewriteRemove.c

@@ -15,9 +15,9 @@
 #include "postgres.h"
 
 #include "access/genam.h"
-#include "access/heapam.h"
 #include "access/htup_details.h"
 #include "access/sysattr.h"
+#include "access/table.h"
 #include "catalog/dependency.h"
 #include "catalog/indexing.h"
 #include "catalog/namespace.h"

src/backend/rewrite/rewriteSupport.c

@@ -14,8 +14,8 @@
  */
 #include "postgres.h"
 
-#include "access/heapam.h"
 #include "access/htup_details.h"
+#include "access/table.h"
 #include "catalog/indexing.h"
 #include "catalog/pg_rewrite.h"
 #include "rewrite/rewriteSupport.h"

src/backend/rewrite/rowsecurity.c

@@ -34,9 +34,9 @@
  */
 #include "postgres.h"
 
-#include "access/heapam.h"
 #include "access/htup_details.h"
 #include "access/sysattr.h"
+#include "access/table.h"
 #include "catalog/pg_class.h"
 #include "catalog/pg_inherits.h"
 #include "catalog/pg_policy.h"