Due to JEP 260 (Encapsulate Most Internal APIs), aspect weaving on
Java 16 now requires '--add-opens java.base/java.lang=ALL-UNNAMED' on
the command line. Otherwise there will be illegal access exceptions for
some internal API calls AspectJ needs, most prominently when trying to
define classes in other packages or modules.

This had to be done on several levels:

  - Maven Surefire: running tests in a JVM directly forked by Surefire.
    In order to make this backwards compatible, I added two profiles
    with JDK-level-dependent auto-activation, one 8-15 and one 16+. In
    the latter a property containing the JVM parameter is defined, in
    the former it is empty, i.e. the JVM is started without the
    parameter. In Java 8 the parameter did not even exist, in Java 9+ we
    could use it, but we need to test how users use AspectJ.

  - RunSpec: Whenever an XML test is declared to use '<run>', we need to
    determine the current JVM version and again dynamically add the
    parameter when forking the target JVM.

  - AntSpec: Whenever an XML test is declared to use '<ant>', we need to
    determine the current JVM version dynamically add two properties
    usable from within Ant scripts: 'aj.addOpensKey' and
    'aj.addOpensValue'. Unfortunately, Ant needs to use two '<argLine>'
    parameters, because the two parts of the option are separated by a
    space character.

  - Ant scripts: When triggered by an AntSpec, each Ant target using LTW
    needs to manually set
      <jvmarg value="${aj.addOpensKey}"/>
      <jvmarg value="${aj.addOpensValue}"/>
    for each '<java>' task. It was quite tedious to find all(?) of them.

TODO: In the AspectJ 1.9.7 release notes we need to document that this
parameter is now needed for LTW.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

This reverts commit a1867b05ba.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

This module must be a relic from a test runner module once existing
during the Ant build era, but transferred and kept alive in the Maven
build. Actually, it almost doubles build time by running virtually all
tests in all modules again when doing 'mvn test' from the project root.

For now I only removed the module from the root POM, leaving behind
comments there, in the module POM and in the now @Deprecated class
RunTheseBeforeYouCommitTests.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

Background: There are CI tests failing because the version is not taken
from the parent POM, even if set in the 'pluginManagement' section.
Instead, it is resolved via the Maven Super POM, e.g. 2.2-beta-5, see:
https://maven.apache.org/ref/3.6.3/maven-model-builder/super-pom.html
That assembly plugin version in turn requires plexus-archiver
1.0-alpha-12. The latter cannot be downloaded from Maven Central,
leading to the problems seen during builds.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

The "old" JUnit-3-style tests will be executed by the vintage-engine

Signed-off-by: Lars Grefer <eclipse@larsgrefer.de>

Signed-off-by: Lars Grefer <eclipse@larsgrefer.de>