WT-12609 Improve checkpoint cleanup and page eviction logic (#10324)

Checkpoint reads only internal pages into the cache for the purpose of
removing any obsolete pages as part of the checkpoint cleanup. Evicting
these internal pages asap can add an overhead to the next checkpoint to
read them back again into the cache. Instead of evicting them asap,
evict the internal pages read by the checkpoint like a regular page.

It is unnecessary to remove leaf pages tagged as READ WONT_NEED from the
cache by the checkpoint because the checkpoint never reads any pages
from the leaf pages (apart from history store pages used for
reconciliation).  This will avoid the unnecessary slowdown of the
checkpoint by evicting the pages that are not read by the checkpoint.

src/btree/bt_sync.c

@@ -326,9 +326,6 @@ __wt_sync_file(WT_SESSION_IMPL *session, WT_CACHE_OP syncop)
         /* Write all dirty in-cache pages. */
         LF_SET(WT_READ_NO_EVICT);
 
-        /* Read pages with history store entries and evict them asap. */
-        LF_SET(WT_READ_WONT_NEED);
-
         /*
          * Perform checkpoint cleanup when not in startup or shutdown phase by traversing internal
          * pages looking for obsolete child pages. This is a form of fast-truncate and so it works
@@ -408,24 +405,22 @@ __wt_sync_file(WT_SESSION_IMPL *session, WT_CACHE_OP syncop)
             }
 
             /*
-             * If the page was pulled into cache by our read, try to evict it now.
+             * When the timing stress is enabled, perform the leaf page eviction by the checkpoint.
              *
              * For eviction to have a chance, we first need to move the walk point to the next page
              * checkpoint will visit. We want to avoid this code being too special purpose, so try
              * to reuse the ordinary eviction path.
              *
              * Regardless of whether eviction succeeds or fails, the walk continues from the
              * previous location. We remember whether we tried eviction, and don't try again. Even
-             * if eviction fails (the page may stay in cache clean but with history that cannot be
-             * discarded), that is not wasted effort because checkpoint doesn't need to write the
-             * page again.
+             * if eviction fails (the page may stay in cache clean), that is not a wasted effort
+             * because checkpoint doesn't need to write the page again.
              *
              * Once the transaction has given up it's snapshot it is no longer safe to reconcile
              * pages. That happens prior to the final metadata checkpoint.
              */
             if (!is_internal &&
-              (__wt_atomic_load64(&page->read_gen) == WT_READGEN_WONT_NEED ||
-                FLD_ISSET(conn->timing_stress_flags, WT_TIMING_STRESS_CHECKPOINT_EVICT_PAGE)) &&
+              FLD_ISSET(conn->timing_stress_flags, WT_TIMING_STRESS_CHECKPOINT_EVICT_PAGE) &&
               !tried_eviction && F_ISSET(session->txn, WT_TXN_HAS_SNAPSHOT)) {
                 ret = __wt_page_release_evict(session, walk, 0);
                 walk = NULL;