Remove unused import

h2/src/main/org/h2/expression/Function.java

@@ -12,12 +12,9 @@ import java.io.InputStreamReader;
 import java.io.Reader;
 import java.nio.charset.StandardCharsets;
 import java.sql.Connection;
-import java.sql.Date;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.ArrayList;
-import java.util.Calendar;
-import java.util.GregorianCalendar;
 import java.util.HashMap;
 import java.util.regex.Pattern;
 import java.util.regex.PatternSyntaxException;