GH-10906: DefaultLockRepository: Use LocalDateTime directly (#10908)

Fixes: #10906

The `Timestamp.valueOf()` method uses the system default time zone which may lead to discrepancy
when daylight saving happens

According to JDBC 4.2+, we don't need to convert `LocalDateTime` to `Timestamp` anymore

* Fix `DefaultLockRepository` to use `LocalDateTime` as values for SQL statements
instead of wrapping them into `Timestamp`

There are no any new tests since this internal change does not affect API logic,
and existing working tests prove that everything is still right

**Auto-cherry-pick to `7.0.x` & `6.5.x`**

Author: artembilan

spring-integration-jdbc/src/main/java/org/springframework/integration/jdbc/lock/DefaultLockRepository.java

@@ -16,7 +16,6 @@
 
 package org.springframework.integration.jdbc.lock;
 
-import java.sql.Timestamp;
 import java.time.Duration;
 import java.time.LocalDateTime;
 import java.time.ZoneOffset;
@@ -440,12 +439,12 @@ public boolean renew(String lock) {
 		return Boolean.TRUE.equals(result);
 	}
 
-	private Timestamp ttlEpochMillis() {
-		return Timestamp.valueOf(currentTime().minus(this.ttl));
+	private LocalDateTime ttlEpochMillis() {
+		return currentTime().minus(this.ttl);
 	}
 
-	private static Timestamp epochMillis() {
-		return Timestamp.valueOf(currentTime());
+	private static LocalDateTime epochMillis() {
+		return currentTime();
 	}
 
 	private static LocalDateTime currentTime() {