RFR: 8298044: Fix hidden but significant trailing whitespace in properties files for langtools code

[Magnus Ihse Bursie]

According to [the specification](https://docs.oracle.com/en/java/javase/19/docs/api/java.base/java/util/Properties.html#load(java.io.Reader)) trailing whitespaces in the values of properties files are (somewhat surprisingly) actually significant.

We have multiple files in the JDK with trailing whitespaces in the values. For most of this files, this is likely incorrect and due to oversight, but in a few cases it might actually be intended (like "The value is: ").

After a discussion in the PR for [JDK-8295729](https://bugs.openjdk.org/browse/JDK-8295729), the consensus was to replace valid trailing spaces with the corresponding unicode sequence, `\u0020`. (And of course remove non-wanted trailing spaces.)

Doing so has a dual benefit:

1) It makes it clear to everyone reading the code that there is a trailing space and it is intended

2) It will allow us to remove all actual trailing space characters, and turn on the corresponding check in jcheck to keep the properties files, just like all other source code files, free of trailing spaces.

Ultimately, the call of whether a trailing space is supposed to be there, or is a bug, lies with the respective component teams owning these files. Thus I have split up the set of properties files with trailing spaces in several groups, to match the JDK teams, and open a JBS issue for each of them. This issue is for code I believe belongs with the langtools team.

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Commit messages:
 - 8298044: Fix hidden but significant trailing whitespace in properties files for langtools code

Changes: https://git.openjdk.org/jdk/pull/11487/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11487&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8298044
  Stats: 18 lines in 10 files changed: 0 ins; 0 del; 18 mod
  Patch: https://git.openjdk.org/jdk/pull/11487.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11487/head:pull/11487

PR: https://git.openjdk.org/jdk/pull/11487