PrintH2DatabaseSchema and ExecuteH2DatabaseStatement shouldn't print stack trace

[DavidWhitlock]

When the database file doesn't exist (or some other exception occurs while running), the PrintH2DatabaseSchema and ExecuteH2DatabaseStatement main methods should not print stack traces. It's not very useful.

Executing SQL: SELECT * FROM customers

Exception in thread "main" org.h2.jdbc.JdbcSQLSyntaxErrorException: Table "CUSTOMERS" not f\
ound (this database is empty); SQL statement:
SELECT * FROM customers [42104-240]
        at org.h2.message.DbException.getJdbcSQLException(DbException.java:514)
        at org.h2.message.DbException.getJdbcSQLException(DbException.java:489)
        at org.h2.message.DbException.get(DbException.java:223)
        at org.h2.message.DbException.get(DbException.java:199)
        at org.h2.command.Parser.getTableOrViewNotFoundDbException(Parser.java:8036)
        at org.h2.command.Parser.getTableOrViewNotFoundDbException(Parser.java:8020)
        at org.h2.command.Parser.readTableOrView(Parser.java:7999)
        at org.h2.command.Parser.readTablePrimary(Parser.java:1772)