RFR: 8278595: Provide more information when a pipeline can't be used [v3]

[Kevin Rushforth]

On Mon, 13 Dec 2021 17:57:21 GMT, Johan Vos <jvos at openjdk.org> wrote:

>> This PR provides at least some basic information when a pipeline can't be used. 
>> There are a number of reasons why a candidate pipeline can't be used, and this PR makes it clear at which point the pipeline fails. 
>> 
>> The changes are only applied in case `prism.verbose` is already set to `true`, so there is no unwanted logging.
>
> Johan Vos has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fix one more whitespace issue

Marked as reviewed by kcr (Lead).

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PR: https://git.openjdk.java.net/jfx/pull/693