This was required by the Eclipse team as one precondition for the next
release.

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

This involves replacing references in weaver application code as well as
a few tests.

In order to make AspectJ weaver + tools contain a relocated ASM version,
I added a Maven Shade relocation step after Maven Assembly created the
uber JARs. Relocation works for both binaries and sources and also
encompasses Class::forName calls like in class AsmDetector.

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

The test class UnweavableTest used ASM 2.0 API. I upgraded in two ways:
  1. Now the ASM 9.1 API is used. Probably works with much older
     versions too (just not as old as 2.0), as long as the method and
     constructor signatures are the same).
  2. The class now uses the AspectJ version of ASM (i.e. package names
     aj.org.objectweb.asm.*) and therefore can just use ASM as it is on
     the classpath for module 'tests' already. There is no more need to
     manually add '<pathelement path="${aj.root}/lib/asm/asm-2.0.jar"/>'
     to the Ant build script for that test.

Consequently, asm-2.0.jar can be eliminated from Git SCM completely,
because it was only used in this one test.

BTW, I also removed some deprecated API and other types of warnings in
UnweavableTest.

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

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>

Modified test expectation system so it is possible to say
the test cares about one particular message and the rest
do not matter (prefix message string with '*') - crude but
quick.

Polished many places to exploit generics

Upgraded all the tests to work on Java8 - some serious changes
regarding ajdoc on Java8. Hopefully it has stayed backwards
compatible with earlier JDK versions (e.g. if using AspectJ 1.8.3+
with a JDK less than 8) but no explicit testing done for this.