RFR: 7903961: Make default timeout configurable

[Christian Stein]

Please review this change replacing the hard-coded `120` seconds default timeout for test actions with a configurable solution parsing a custom default value from `TEST.ROOT` and `TEST.properties` files.

Especially in combination with "JUnit.dirs" and "TestNG.dirs", where all actions directives found in a test file are ignored, is helpful.

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Commit messages:
 - Add tag-spec entry
 - Increase expected test pass count
 - 7903961: Make default timeout configurable

Changes: https://git.openjdk.org/jtreg/pull/253/files
  Webrev: https://webrevs.openjdk.org/?repo=jtreg&pr=253&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7903961
  Stats: 88 lines in 7 files changed: 76 ins; 2 del; 10 mod
  Patch: https://git.openjdk.org/jtreg/pull/253.diff
  Fetch: git fetch https://git.openjdk.org/jtreg.git pull/253/head:pull/253

PR: https://git.openjdk.org/jtreg/pull/253