RFR: 8370100: Redundant .png files in Linux app-image cause unnecessary bloat [v2]

[Alexey Semenyuk]

> Don't put the default icon (.png) files in the app image on Linux.

Alexey Semenyuk has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains eight new commits since the last revision:

 - DefaultLauncherIcon: blessed-modifier-order.sh  fix
 - FileAssociations: revert redundant change
 - Fix fa icon verification on Linux
 - LinuxPackagingPipeline, WinPackagingPipeline: remove unused normalizeShortcuts() methods
 - IconTest: revamp
 - LinuxHelper: revamp
 - Don't add the default launcher icon to app image on Linux
 - Make Launcher interface provide complete information about the source of the launcher icon; Before this change, the function getting a resource for an additional launcher icon took both the additional launcher and the main launcher as input. Now its result doesn't depend on the main launcher.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/27928/files
  - new: https://git.openjdk.org/jdk/pull/27928/files/15ef5d5a..0ad210ba

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27928&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27928&range=00-01

  Stats: 110 lines in 6 files changed: 40 ins; 62 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/27928.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27928/head:pull/27928

PR: https://git.openjdk.org/jdk/pull/27928