Fix Java flags in TF template to work with JDK 17+

Isolated TF tests are failing since the `--add-exports` option cannot be
parsed by JDK 17+ due to a missing '<target-module>' component. This
change resolves the issue by adjusting the options in the TF template to
export the source package to all unnamed modules.

See
https://docs.oracle.com/javase/9/migrate/toc.htm#JSMIG-GUID-2F61F3A9-0979-46A4-8B49-325BA0EE8B66
for more information.

Test: atest --host HelloWorldHostTest
Change-Id: Iccb8a8dcd3707237e018d6feb6b6a0e8d2bc9a86