RFR: Made jdec to write output to proer toolOutput instead of bad logOutput

[Jiří Vaněk]

Hello!

This is fixing the bad streams of jdec in at8, and is making the tests in https://urldefense.com/v3/__https://github.com/openjdk/asmtools/pull/23__;!!ACWV5N9M2RV99hQ!JiuQWTbxOAQu0Dy9JtVECsBX4m9pFfH6HWamO6JIQKH26RUifrkJtKOES1vCuYCZ6XQHKW50H7AoFJlJF1GROw$  to pass

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Commit messages:
 - Made jdec to write output to proper toolOutput instead of bad logOutput

Changes: https://git.openjdk.org/asmtools/pull/24/files
 Webrev: https://webrevs.openjdk.org/?repo=asmtools&pr=24&range=00
  Stats: 10 lines in 1 file changed: 7 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/asmtools/pull/24.diff
  Fetch: git fetch https://git.openjdk.org/asmtools pull/24/head:pull/24

PR: https://git.openjdk.org/asmtools/pull/24