RFR: 8287828: Fix so that one can select jtreg test case by ID from make [v6]

[Leo Korinth]

On Mon, 27 Jun 2022 14:27:36 GMT, Leo Korinth <lkorinth at openjdk.org> wrote:

>> One can select a testcase by ID when running a jtreg test case directly from jtreg (using the testcase.java#testID syntax). However, this has not been possible to do when launching jtreg indirectly from make.
>> 
>> This fix attempts to address this issue. I have not tested this thoroughly yet, I wanted to show the code to get feedback first. The idea is to *not* emulated destructive imperative assignments through the use of eval. I instead try to handle it in a functional style without reassigning variables. I have tried to make the change as small as possible.
>> 
>> I am not used to change the build system, so I would appreciate thorough review.
>> 
>> `IfAppend` and `IfPrepend` are general purpose functions. If similar functions exists elsewhere inside the code base or in make itself I should probably use those instead. If they do not exist, they might be useful elsewhere and maybe should be placed in a common make file instead of the RunTests.gmk file.
>
> Leo Korinth has updated the pull request incrementally with one additional commit since the last revision:
> 
>   remove one unnessesary $(subst)

I removed one unnecessary `$(subst)`, I think it was a leftover from an early version that striped the hash character from the id.

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PR: https://git.openjdk.org/jdk/pull/9028