RFR: 8295729: Add jcheck whitespace checking for properties files [v2]

[Magnus Ihse Bursie]

> 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:

 - Remove check for .properties from jcheck
 - Restore trailing whitespace for property values

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/10792/files
  - new: https://git.openjdk.org/jdk/pull/10792/files/e33c0765..c91fdaa1

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10792&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10792&range=00-01

  Stats: 412 lines in 131 files changed: 0 ins; 0 del; 412 mod
  Patch: https://git.openjdk.org/jdk/pull/10792.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10792/head:pull/10792

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