Avoid potential integer overflow in seconds->millis transformation

Closes gh-25613

spring-context/src/main/java/org/springframework/context/support/AbstractResourceBasedMessageSource.java

@@ -173,7 +173,7 @@ protected boolean isFallbackToSystemLocale() {
 	 * a non-classpath location.
 	 */
 	public void setCacheSeconds(int cacheSeconds) {
-		this.cacheMillis = (cacheSeconds * 1000);
+		this.cacheMillis = cacheSeconds * 1000L;
 	}
 
 	/**