Resolve birthmarks during eviction in more cases

[1538649381:68593][39477:0x7ffbc4b2e700], test_timestamp04.test_timestamp04.test_rollback_to_stable(nolog.col_var), file:ts04_ts_nologged.wt, eviction-server: __rec_append_orig_value, 1220: unpack != NULL && unpack->type != WT_CELL_DEL

[1538649381:68789][39477:0x7ffbc4b2e700], test_timestamp04.test_timestamp04.test_rollback_to_stable(nolog.col_var), file:ts04_ts_nologged.wt, eviction-server: __wt_abort, 30: aborting WiredTiger library

#2  0x00007ffbc8fbfe00 in __wt_abort (session=0x35263d8) at ../src/os_common/os_abort.c:32

#3  0x00007ffbc8fdb1d5 in __rec_append_orig_value (session=0x35263d8, page=0x4278cb0, upd=0x6b87b20, unpack=0x7ffbc4b2db30) at ../src/reconcile/rec_write.c:1219

#4  0x00007ffbc8fdbcdf in __rec_txn_read (session=0x35263d8, r=0x7ffb9c0098b0, ins=0x2c604f0, ripcip=0x4278d00, vpack=0x7ffbc4b2db30, upd_savedp=0x0, 

    updp=0x7ffbc4b2db20) at ../src/reconcile/rec_write.c:1607

#5  0x00007ffbc8fe2634 in __rec_col_var (session=0x35263d8, r=0x7ffb9c0098b0, pageref=0x82497c0, salvage=0x0) at ../src/reconcile/rec_write.c:4766

#6  0x00007ffbc8fd9597 in __wt_reconcile (session=0x35263d8, ref=0x82497c0, salvage=0x0, flags=138, lookaside_retryp=0x0) at ../src/reconcile/rec_write.c:474

#7  0x00007ffbc8f8a694 in __evict_review (session=0x35263d8, ref=0x82497c0, closing=false, inmem_splitp=0x7ffbc4b2dd7e) at ../src/evict/evict_page.c:685

#8  0x00007ffbc8f892d3 in __wt_evict (session=0x35263d8, ref=0x82497c0, closing=false, previous_state=5) at ../src/evict/evict_page.c:174

#9  0x00007ffbc8f862f1 in __evict_page (session=0x35263d8, is_server=false) at ../src/evict/evict_lru.c:2322

#10 0x00007ffbc8f82a29 in __evict_lru_pages (session=0x35263d8, is_server=false) at ../src/evict/evict_lru.c:1173

#11 0x00007ffbc8f80ba8 in __wt_evict_thread_run (session=0x35263d8, thread=0x9ac6300) at ../src/evict/evict_lru.c:318

#12 0x00007ffbc9021b98 in __thread_run (arg=0x9ac6300) at ../src/support/thread_group.c:31

#13 0x00007ffbd1bdddc5 in start_thread (arg=0x7ffbc4b2e700) at pthread_create.c:308

cell.i: #define WT_CELL_DEL              (4 << 4)       /* Deleted value */

1217			/* Add the original value after birthmarks. */

1218			if (upd->type == WT_UPDATE_BIRTHMARK) {

1219				WT_ASSERT(session, unpack != NULL &&

1220				    unpack->type != WT_CELL_DEL);

1221				break;

1222			}

1223	

(gdb) p unpack

$1 = (WT_CELL_UNPACK *) 0x7ffbc4b2db30

(gdb) p *unpack

$2 = {cell = 0x427a138, v = 148, data = 0x0, size = 0, __len = 3, prefix = 0 '\000', raw = 64 '@', type = 64 '@', ovfl = 0 '\000'}