修复failover发生后主机在回放阶段淘汰了从备机要到的需要flush的页面, 导致磁盘上页面漏刷的问题

src/gausskernel/storage/buffer/bufmgr.cpp

@@ -620,6 +620,11 @@ static volatile BufferDesc *PageListBufferAlloc(SMgrRelation smgr, char relpersi
         /* Pin the buffer and then release the buffer spinlock */
         PinBuffer_Locked(buf);
 
+        if (!SSPageCheckIfCanEliminate(buf)) {
+            UnpinBuffer(buf, true);
+            return NULL;
+        }
+
         /*
          * At this point, the victim buffer is pinned
          * but no locks are held.

src/gausskernel/storage/smgr/segment/segbuffer.cpp

@@ -704,6 +704,11 @@ BufferDesc *SegBufferAlloc(SegSpace *spc, RelFileNode rnode, ForkNumber forkNum,
 
         SegPinBufferLocked(buf, &new_tag);
 
+        if (!SSPageCheckIfCanEliminate(buf)) {
+            SegUnpinBuffer(buf);
+            continue;
+        }
+
         if (old_flags & BM_DIRTY) {
             /* backend should not flush dirty pages if working version less than DW_SUPPORT_NEW_SINGLE_FLUSH */
             if (!backend_can_flush_dirty_page()) {