RFR: Unstuck version

[Jiří Vaněk]

Hello! This pr is solving - and is not - the hanged waiting for stdin for no file argument.
1) it properly exits after version is printed, thus is unaffected by any file arguments (and streams) which may change alter
2) it changes the Stream (and extending) input implemetation to lazily drain the stream once needed, not durign construction. TBH, I'm not sure with this change, but I was generally very unhappy  by draining the stream in cosntructor at all. This alone, would not solve the -version problem, because the StreamInput is added always, and thus is always processed, thus stdin is read no meter if it is lazy or in constructor.

This intentionally do not add the empty "-" switch. That may come later as needed.

Hints welcomed!

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Commit messages:
 - Stream based inputs are now drained once needed, not during construction
 - Properly exiting after verson is printed

Changes: https://git.openjdk.org/asmtools/pull/36/files
 Webrev: https://webrevs.openjdk.org/?repo=asmtools&pr=36&range=00
  Stats: 40 lines in 7 files changed: 30 ins; 0 del; 10 mod
  Patch: https://git.openjdk.org/asmtools/pull/36.diff
  Fetch: git fetch https://git.openjdk.org/asmtools pull/36/head:pull/36

PR: https://git.openjdk.org/asmtools/pull/36