[wip] Fix empty join conditions query failure

[SemionPar]

Description

Reproduce "joinConditions is empty" error

Additional context and related issues

Bisected to 91a29a7

SELECT a.c_num FROM left a LEFT JOIN right b ON DATE '2025-03-19' = b.c_date;

Query of this shape results in

Caused by: com.google.common.base.VerifyException: joinConditions is empty
	at com.google.common.base.Verify.verify(Verify.java:126)
	at io.trino.plugin.jdbc.DefaultQueryBuilder.prepareJoinQuery(DefaultQueryBuilder.java:126)
	at io.trino.plugin.jdbc.BaseJdbcClient.implementJoin(BaseJdbcClient.java:537)
	at io.trino.plugin.postgresql.PostgreSqlClient.lambda$implementJoin$13(PostgreSqlClient.java:1074)
	at io.trino.plugin.jdbc.JdbcJoinPushdownUtil.implementJoinCostAware(JdbcJoinPushdownUtil.java:46)
	at io.trino.plugin.postgresql.PostgreSqlClient.implementJoin(PostgreSqlClient.java:1068)
	at io.trino.plugin.jdbc.ForwardingJdbcClient.implementJoin(ForwardingJdbcClient.java:220)
	at io.trino.plugin.jdbc.jmx.StatisticsAwareJdbcClient.lambda$implementJoin$20(StatisticsAwareJdbcClient.java:239)
	at io.trino.plugin.jdbc.jmx.JdbcApiStats.wrap(JdbcApiStats.java:34)
	at io.trino.plugin.jdbc.jmx.StatisticsAwareJdbcClient.implementJoin(StatisticsAwareJdbcClient.java:239)
	at io.trino.plugin.jdbc.CachingJdbcClient.implementJoin(CachingJdbcClient.java:293)
	at io.trino.plugin.jdbc.CachingJdbcClient.implementJoin(CachingJdbcClient.java:293)
	at io.trino.plugin.jdbc.DefaultJdbcMetadata.applyJoin(DefaultJdbcMetadata.java:497)
	at io.trino.plugin.base.classloader.ClassLoaderSafeConnectorMetadata.applyJoin(ClassLoaderSafeConnectorMetadata.java:1042)
	at io.trino.tracing.TracingConnectorMetadata.applyJoin(TracingConnectorMetadata.java:1206)
	at io.trino.metadata.MetadataManager.applyJoin(MetadataManager.java:1957)
	at io.trino.tracing.TracingMetadata.applyJoin(TracingMetadata.java:988)
	at io.trino.sql.planner.iterative.rule.PushJoinIntoTableScan.apply(PushJoinIntoTableScan.java:149)
	at io.trino.sql.planner.iterative.rule.PushJoinIntoTableScan.apply(PushJoinIntoTableScan.java:68)
	at io.trino.sql.planner.iterative.IterativeOptimizer.transform(IterativeOptimizer.java:209)
	at io.trino.sql.planner.iterative.IterativeOptimizer.exploreNode(IterativeOptimizer.java:176)
	at io.trino.sql.planner.iterative.IterativeOptimizer.exploreGroup(IterativeOptimizer.java:139)
	at io.trino.sql.planner.iterative.IterativeOptimizer.exploreChildren(IterativeOptimizer.java:259)
	at io.trino.sql.planner.iterative.IterativeOptimizer.exploreGroup(IterativeOptimizer.java:141)
	at io.trino.sql.planner.iterative.IterativeOptimizer.optimize(IterativeOptimizer.java:123)
	at io.trino.sql.planner.LogicalPlanner.runOptimizer(LogicalPlanner.java:309)
	at io.trino.sql.planner.LogicalPlanner.plan(LogicalPlanner.java:270)
	at io.trino.sql.planner.LogicalPlanner.plan(LogicalPlanner.java:239)
	at io.trino.sql.planner.LogicalPlanner.plan(LogicalPlanner.java:234)
	at io.trino.execution.SqlQueryExecution.doPlanQuery(SqlQueryExecution.java:486)
	at io.trino.execution.SqlQueryExecution.planQuery(SqlQueryExecution.java:466)
	at io.trino.execution.SqlQueryExecution.start(SqlQueryExecution.java:404)
	at io.trino.execution.SqlQueryManager.createQuery(SqlQueryManager.java:264)
	at io.trino.dispatcher.LocalDispatchQuery.startExecution(LocalDispatchQuery.java:145)
	at io.trino.dispatcher.LocalDispatchQuery.lambda$waitForMinimumWorkers$2(LocalDispatchQuery.java:129)
	at io.airlift.concurrent.MoreFutures.lambda$addSuccessCallback$12(MoreFutures.java:568)
	at io.airlift.concurrent.MoreFutures$3.onSuccess(MoreFutures.java:543)
	at com.google.common.util.concurrent.Futures$CallbackListener.run(Futures.java:1133)
	at io.trino.$gen.Trino_testversion____20250430_152414_75.run(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
	at java.base/java.lang.Thread.run(Thread.java:1583)

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## Section
* Fix some things. ({issue}`issuenumber`)