logictest: improve contention_event

Switch to the 5node family of clusters to test against (more realistic),
and also make the query that collects the event touch multiple ranges,
which make it "easier" to miss an event.

cc @irfansharif - this could help with the discussion about DistSender
in [1].

[1]: #59815

Release note: None

pkg/sql/logictest/testdata/logic_test/contention_event

@@ -1,3 +1,5 @@
+# LogicTest: 5node
+#
 # Verify that ContentionEvents are emitted. This is mostly a sanity check - look
 # for the datadriven tests in `pkg/kv/kvserver/concurrency` for the actual events
 # that do get emitted in various contention scenarios.
@@ -6,7 +8,8 @@ statement ok
 GRANT ADMIN TO testuser
 
 statement ok
-CREATE TABLE kv (k VARCHAR PRIMARY KEY, v VARCHAR)
+CREATE TABLE kv (k VARCHAR PRIMARY KEY, v VARCHAR);
+ALTER TABLE kv SPLIT AT VALUES ('b'), ('d'), ('q'), ('z');
 
 
 query TT
@@ -26,22 +29,30 @@ user root
 statement ok
 SET tracing=on
 
+# Scan all ranges of the table (note that we have intentionally
+# split it into at least six ranges). This is better than a point
+# lookup in that it gives tracing more of a chance to get things
+# wrong due to DistSender parallelism.
 statement ok
 SET TRACING=on;
 BEGIN;
 SET TRANSACTION PRIORITY HIGH;
-INSERT INTO kv VALUES('k', 'my v');
+SELECT * FROM kv;
 COMMIT;
 SET TRACING=off;
 
 # Check for the message emitted by (roachpb.ContentionEvent).String() as proof that a ContentionEvent
 # payload was added to the trace.
 #
+# NB: it looks like there can be multiple (probably when there's an internal restart
+# or something like that). Unfortunately, it is difficult in logic tests to log something
+# that is not part of the scripted output.
+#
 # NB: if the matcher here ever gets updated, make sure to update throughout this file.
-query I
-SELECT count(message) FROM [ SHOW TRACE FOR SESSION ] WHERE message LIKE '%conflicted with % on % for %'
+query B
+SELECT count(message) > 0 FROM [ SHOW TRACE FOR SESSION ] WHERE message LIKE '%conflicted with % on % for %'
 ----
-1
+true
 
 # Clean up.
 user testuser