RFR: 8355651: Premature execution of post-image hook

[Alexey Semenyuk]

Reorder the calling of a custom "post-image" script in MSI packaging.

Add a relevant test.

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Commit messages:
 - Test the current directory of the post-image script is the root directory for app image.
 - 8355651: Premature execution of post-image hook

Changes: https://git.openjdk.org/jdk/pull/24899/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24899&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8355651
  Stats: 105 lines in 2 files changed: 61 ins; 21 del; 23 mod
  Patch: https://git.openjdk.org/jdk/pull/24899.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24899/head:pull/24899

PR: https://git.openjdk.org/jdk/pull/24899