RFR: 8317283: jpackage tests run osx-specific checks on windows and linux

[Alexey Semenyuk]

- Don't run osx specific checks on Linux and Windows
 - Rework checks output from 

[17:31:52.845] TRACE: assertTrue(): Unexptected value in app image file for <signed>
[17:31:52.860] TRACE: assertTrue(): Unexptected value in app image file for <app-store>

to

[22:07:46.519] TRACE: assertEquals(false): Check for unexptected value in app image file for <signed>
[22:07:46.519] TRACE: assertEquals(false): Check for unexptected value in app image file for <app-store>

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

Commit messages:
 - 8317283: jpackage tests run osx-specific checks on windows and linux

Changes: https://git.openjdk.org/jdk/pull/15975/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15975&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8317283
  Stats: 11 lines in 1 file changed: 4 ins; 0 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/15975.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15975/head:pull/15975

PR: https://git.openjdk.org/jdk/pull/15975