RFR: 7904074: Introduce a way to disallow certain test actions [v2]

[Jaikiran Pai]

> Can I please get a review of this enhancement which introduces the ability to configure test actions which are disallowed to be used in test definitions? This addresses https://bugs.openjdk.org/browse/CODETOOLS-7904074.
> 
> This introduces a new `disallowedActions` test configuration, which can be set in `TEST.ROOT` or `TEST.properties` file(s) to allow projects to configure test actions that aren't allowed for those projects. For example, the JDK project could be configured with:
> 
> 
> disallowedActions=applet
> 
> so that any new (or existing) test definitions with a `@run applet` will cause those tests to error.
> 
> A new self test has been introduced which verifies this feature. I have also run manual tests to make sure that this feature can be used in the JDK.

Jaikiran Pai has updated the pull request incrementally with two additional commits since the last revision:

 - another final
 - Christian's review - remove final

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

Changes:
  - all: https://git.openjdk.org/jtreg/pull/285/files
  - new: https://git.openjdk.org/jtreg/pull/285/files/5b786708..aaeff5a0

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jtreg&pr=285&range=01
 - incr: https://webrevs.openjdk.org/?repo=jtreg&pr=285&range=00-01

  Stats: 8 lines in 2 files changed: 0 ins; 0 del; 8 mod
  Patch: https://git.openjdk.org/jtreg/pull/285.diff
  Fetch: git fetch https://git.openjdk.org/jtreg.git pull/285/head:pull/285

PR: https://git.openjdk.org/jtreg/pull/285