RFR: JDK-8246705: javadoc gives "misleading" and incomplete warning message.

[Hannes Wallnoefer]

Looks good to me. 

I can’t quite work out why the message in testExplicitBinaryModuleOnLegacyPaths changes from module_not_found to module_not_found_on_sourcepath instead of module_source_not_found, but it seems like the correct message in the context.

Hannes

> Am 06.06.2020 um 01:48 schrieb Jonathan Gibbons <jonathan.gibbons at oracle.com>:
> 
> Please review a small change to a poor warning message that is generated in unusual circumstances. The circumstances are caused by using --expand-requires and not having the source available for all the modules.
> 
> 	• The message incorrectly uses the simple name of a module instead of the fully qualified name.
> The fix is trivial: use the fully qualified name
> 	• The message is too broad and says "module not found" when it really means "source for module not found"
> The message is improved
> 	• The message may be unnecessarily repeated.
> To minimize risk of a complicated solution, a simple cache is used to track instances of the warnings to avoid duplicates.
> In addition, a couple of inappropriate trailing periods are removed from a couple of related messages.
> 
> Two tests are updated; one test is marked for this bug.
> 
> -- Jon
> 
> JBS: https://bugs.openjdk.java.net/browse/JDK-8246705
> Webrev: http://cr.openjdk.java.net/~jjg/8246705/webrev.00/
>