RFR: JDK-8297215: Update libs tests to use @enablePreview [v5]

[Joe Darcy]

> Similar to an update recently done for langtools tests, update the libraries regression tests to take advantage of the @enablePreview jtreg feature.

Joe Darcy has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains seven additional commits since the last revision:

 - Remove unnecessary @compile directives.
 - Merge branch 'master' into JDK-8297215
 - Respond to review feedback.
 - Respond to review feedback.
 - Merge branch 'master' into JDK-8297215
 - Respond to review feedback.
 - JDK-8297215: Update libs tests to use @enablePreview

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/11222/files
  - new: https://git.openjdk.org/jdk/pull/11222/files/c0bef63e..d03ba044

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11222&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11222&range=03-04

  Stats: 6073 lines in 149 files changed: 3996 ins; 1399 del; 678 mod
  Patch: https://git.openjdk.org/jdk/pull/11222.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11222/head:pull/11222

PR: https://git.openjdk.org/jdk/pull/11222