RFR: 8281682: Redundant .ico files in Windows app-image cause unnecessary bloat

[Alexey Semenyuk]

8281682: Redundant .ico files in Windows app-image cause unnecessary bloat

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Commit messages:
 - Trailing whitespace removed
 - Drop unused WinIconVerifierException
 - remove accidentally added space char
 - jtreg descriptions fixed
 - 8281682: Redundant .ico files in Windows app-image cause unnecessary bloat

Changes: https://git.openjdk.java.net/jdk/pull/8794/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8794&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8281682
  Stats: 169 lines in 8 files changed: 150 ins; 6 del; 13 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8794.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8794/head:pull/8794

PR: https://git.openjdk.java.net/jdk/pull/8794