RFR: Added missing flushes

[Jiří Vaněk]

If the asmtools are used as library, and not just a cmdline tool, then it become visible, that stdouts are not properly closed.
This pr is adding flusehs jdis and jdec. Maybe the issue is more spread, but I was not using other parts library (yet)

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Commit messages:
 - Fixed missing flush for jdec
 - Fixed missing flush for jdis

Changes: https://git.openjdk.java.net/asmtools/pull/16/files
 Webrev: https://webrevs.openjdk.java.net/?repo=asmtools&pr=16&range=00
  Stats: 2 lines in 2 files changed: 2 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/asmtools/pull/16.diff
  Fetch: git fetch https://git.openjdk.java.net/asmtools pull/16/head:pull/16

PR: https://git.openjdk.java.net/asmtools/pull/16