12 RFR (XS) 8215301: Module-summary page is unreadably wide

[mark.reinhold at oracle.com]

Bug: https://bugs.openjdk.java.net/browse/JDK-8215301
Webrev: https://cr.openjdk.java.net/~mr/rev/8215301/

The `make generate-summary` target produces a handy tabular summary
of all of the modules in a JDK build into
`$BUILD/images/gengraphs/module-summary.html`. Several JDK modules
(e.g., `java.desktop` and `jdk.internal.vm.compiler`) include many
providers for a particular service, and the providers are all listed
in a single line, resulting in a very wide HTML page that’s difficult
to read even on a large screen.

Output before: https://cr.openjdk.java.net/~mr/rev/8215301/module-summary-old.html
After: https://cr.openjdk.java.net/~mr/rev/8215301/module-summary-new.html

Thanks,
- Mark