RFR: notify: create test utils

[Erik Helin]

Hi all,

please review this patch that moves some static utility functions out from a unit test and into a proper `TestUtils`
class.

Testing:
- [x] `make test` passes on Linux x64

Thanks,
Erik

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Commit messages:
 - notify: create test utils

Changes: https://git.openjdk.java.net/skara/pull/652/files
 Webrev: https://webrevs.openjdk.java.net/skara/652/webrev.00
  Stats: 63 lines in 5 files changed: 44 ins; 15 del; 4 mod
  Patch: https://git.openjdk.java.net/skara/pull/652.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/652/head:pull/652

PR: https://git.openjdk.java.net/skara/pull/652