RFR: 8295729: Add jcheck whitespace checking for properties files [v3]

[Magnus Ihse Bursie]

On Mon, 24 Oct 2022 19:21:07 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

>> Properties files is essentially source code. It should have the same whitespace checks as all other source code, so we don't get spurious trailing whitespace changes.
>> 
>> With the new Skara jcheck, it is possible to increase the coverage of the whitespace checks (in the old mercurial version, this was more or less impossible).
>> 
>> The only manual change is to `.jcheck/conf`. All other changes were made by running `find . -type f -iname "*.properties" | xargs gsed -i -e 's/[ \t]*$//'`.
>
> Magnus Ihse Bursie has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Revert "Remove check for .properties from jcheck"
>    
>    This reverts commit c91fdaa19dc06351598bd1c0614e1af3bfa08ae2.
>  - Change trailing space and tab in values to unicode encoding

This turned out to be much more complicated than anticipated. I am going to close this PR (and bug), and instead I have split up this work in five different bugs:

[JDK-8298047](https://bugs.openjdk.org/browse/JDK-8298047) is about removing all non-significant whitespace from all properties files, basically corresponding to how this PR looked after the second commit.

[JDK-8298042](https://bugs.openjdk.org/browse/JDK-8298042), [JDK-8298044](https://bugs.openjdk.org/browse/JDK-8298044), [JDK-8298045](https://bugs.openjdk.org/browse/JDK-8298045) and [JDK-8298046](https://bugs.openjdk.org/browse/JDK-8298046) is about fixing the significant whitespace, by turning it to unicode sequences or removing it, if it turns out there should not have been a space there. This work is split into four parts to be able to have one bug per component team.

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PR: https://git.openjdk.org/jdk/pull/10792