RFR: 8333358: java/io/IO/IO.java test fails intermittently

[Pavel Rappo]

Please review this fix for an intermittent test failure.

On some configurations, the default `expect` timeout of 10 seconds is insufficient. It is increased to 20; it's hard to imagine a configuration for which that new value would still be insufficient, but we'll see.

Aside from that, test-generated diagnostics are improved: the version of the `expect` command and the duration of each test method are recorded. `output.exp` is modified for robustness and clear indication of the timeout condition.

I was reminded, out-of-band, that test timeouts should be scaled with `test.timeout.factor`. I propose to integrate this PR first and then separately update all the affected tests to scale their `expect` timeouts.

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

Commit messages:
 - Initial commit

Changes: https://git.openjdk.org/jdk/pull/19627/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19627&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8333358
  Stats: 68 lines in 3 files changed: 62 ins; 2 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/19627.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19627/head:pull/19627

PR: https://git.openjdk.org/jdk/pull/19627