RFR: 8343100: Consolidate EmptyFolderTest and EmptyFolderPackageTest jpackage tests into single java file [v2]

[Alexey Semenyuk]

> - merge EmptyFolderTest, EmptyFolderPackageTest and EmptyFolderTestBase in EmptyFolderTest class.
>  - for .msi packaging still verify the output. It should not contain empty folders from `--input`, but should contain other folders and files from `--input`.
> - fixed `TKit.assertPathNotEmptyDirectory()` that didn't fail if the given path was not a directory.
> - renamed `TKit.assertPathNotEmptyDirectory()` into `TKit.assertDirectoryNotEmpty()` for consistency
> - added `TKit.assertDirectoryEmpty()`
> - replaced some `TKit.assertFalse()` calls with `TKit.assertTrue()` to improve test log readibilty. Old:
> 
> [17:04:16.189] TRACE: assertFalse(): Check [...] path doesn't exist
> 
> New:
> 
> [17:04:16.189] TRACE: assertTrue(): Check [...] path doesn't exist

Alexey Semenyuk has updated the pull request incrementally with one additional commit since the last revision:

  Bugfix

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/21721/files
  - new: https://git.openjdk.org/jdk/pull/21721/files/c9f59f12..894db578

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21721&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21721&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/21721.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21721/head:pull/21721

PR: https://git.openjdk.org/jdk/pull/21721