[jdk8u-dev] RFR: 8253424: Add support for running pre-submit testing using GitHub Actions

[Andrew John Hughes]

Initial attempt to backport https://github.com/openjdk/jdk11u-dev/commit/1faefed218051c324bdb5c7c10369050d6c9dd44

Changes so far:
* make/autoconf/version-numbers -> common/autoconf/version-numbers
* Fix version variables (JDK_MAJOR_VERSION, JDK_MINOR_VERSION and JDK_MICRO_VERSION in 8u)
* Remove boot JDK for Linux (provided by build environment Ubuntu 20.04 in openjdk-8-jdk)

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

Commit messages:
 - Backport 1faefed218051c324bdb5c7c10369050d6c9dd44

Changes: https://git.openjdk.java.net/jdk8u-dev/pull/3/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk8u-dev&pr=3&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8253424
  Stats: 1454 lines in 2 files changed: 1454 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk8u-dev/pull/3.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk8u-dev pull/3/head:pull/3

PR: https://git.openjdk.java.net/jdk8u-dev/pull/3