[Java] Remove duplicate Preconditions check in JDBC adapter

[asfimport]

Some Preconditions check are duplicate in JdbcToArrow#sqlToArrow

Reporter: Ji Liu / @tianchen92
Assignee: Ji Liu / @tianchen92

PRs and other links:

• GitHub Pull Request #4896

_{Note: This issue was originally created as ARROW-5968. Please see the migration documentation for further details.}

[asfimport]

Micah Kornfield / @emkornfield:
Issue resolved by pull request 4896
#4896