Deadlock during test with basic_archive

[abigalekim]

Reproducibility info:

• Postgres 15.3
• Ubuntu 22.04
• the basic_archive extension is also from the contrib directory of Postgres 15.3
• shared_preload_libraries has lsm3,basic_archive in that order

Here are the diffs from the lsm3 test:

diff -U3 /Users/abigale/code/cmu/pgext-cli-python/pgextworkdir/lsm3/expected/test.out /Users/abigale/code/cmu/pgext-cli-python/testing-output-06-20-2023_19:46/lsm3_basic_archive/results/test.out
--- /Users/abigale/code/cmu/pgext-cli-python/pgextworkdir/lsm3/expected/test.out	2023-06-20 19:47:34.000000000 -0400
+++ /Users/abigale/code/cmu/pgext-cli-python/testing-output-06-20-2023_19:46/lsm3_basic_archive/results/test.out	2023-06-20 19:47:45.000000000 -0400
@@ -150,19 +150,29 @@
 (1 row)
 
 truncate table t;
+ERROR:  deadlock detected
+DETAIL:  Process 92214 waits for AccessExclusiveLock on relation 17035 of database 16384; blocked by process 92215.
+Process 92215 waits for AccessShareLock on relation 17030 of database 16384; blocked by process 92214.
+HINT:  See server log for query details.
 insert into t values (generate_series(1,1000000), 1);
 select * from t where k = 1;
  k | val 
 ---+-----
+ 1 |  10
  1 |   1
-(1 row)
+ 1 |   1
+ 1 |   1
+(4 rows)
 
 reindex table t;
 select * from t where k = 1;
  k | val 
 ---+-----
+ 1 |  10
  1 |   1
-(1 row)
+ 1 |   1
+ 1 |   1
+(4 rows)
 
 drop table t;
 create table lsm(k bigint);