Fix accessibility of tables in the java.desktop module

There are a number of tables in the API docs for the java.desktop module that need to be updated for accessibility. In the following table, the entries for <unset> borderless, plain, striped all need attention.

Accessibility: Tables Report

Checked 4079 tables in 1890 files.

<unset> 7 0 0%
borderless 15 0 0%
memberSummary 3583 3583 100%
packagesSummary 2 2 100%
plain 2 0 0%
requiresSummary 1 1 100%
striped 36 0 0%
typeSummary 113 113 100%
useSummary 319 319 100%
usesSummary 1 1 100%
TOTAL 4079 4019 98%

(See attached report java.desktop.html for a more complete and easily readable report on the API docs for the java.desktop module)