Insufficient triggers for classpath validation

[stephan-herrmann]

fixes #202

one-line fix, I still need to provide tests for it.

[stephan-herrmann]

It turned out that JavaProject already listens to preference changes adding a classpath validation as needed. I just had to enable this for one more option: --release.

Unfortunately, builds are not feeling well today, o.e.j.core.tests.compiler doesn't find jdt.annotations 2.x which was successfully built in the same reactor....

[iloveeclipse]

@stephan-herrmann : could you please fix new test failure in I20220714-1800 ?

https://download.eclipse.org/eclipse/downloads/drops4/I20220714-1800/testresults/html/org.eclipse.jdt.core.tests.model_ep425I-unit-cen64-gtk3-java11_linux.gtk.x86_64_11.html

xpected markers. ----------- Expected ------------ Exporting a package from system module 'java.desktop' is not allowed with --release.\n The project cannot be built until build path errors are resolved ------------ but was ------------ The project cannot be built until build path errors are resolved\n Exporting a package from system module 'java.desktop' is not allowed with --release. --------- Difference is ---------- expected:<[Exporting a package from system module 'java.desktop' is not allowed with --release.\n The project cannot be built until build path errors are resolved]> but was:<[The project cannot be built until build path errors are resolved\n Exporting a package from system module 'java.desktop' is not allowed with --release.]>

junit.framework.ComparisonFailure: Unexpected markers.
----------- Expected ------------
Exporting a package from system module 'java.desktop' is not allowed with --release.\n
The project cannot be built until build path errors are resolved
------------ but was ------------
The project cannot be built until build path errors are resolved\n
Exporting a package from system module 'java.desktop' is not allowed with --release.
--------- Difference is ----------
expected:<[Exporting a package from system module 'java.desktop' is not allowed with --release.\n
The project cannot be built until build path errors are resolved]> but was:<[The project cannot be built until build path errors are resolved\n
Exporting a package from system module 'java.desktop' is not allowed with --release.]>
at org.eclipse.jdt.core.tests.junit.extension.TestCase.assertStringEquals(TestCase.java:266)
at org.eclipse.jdt.core.tests.junit.extension.TestCase.assertEquals(TestCase.java:242)
at org.eclipse.jdt.core.tests.model.AbstractJavaModelTests.assertMarkers(AbstractJavaModelTests.java:1064)
at org.eclipse.jdt.core.tests.model.ModuleBuilderTests.testAddExportsIllegal(ModuleBuilderTests.java:4810)

[iloveeclipse]

could you please fix new test failure in I20220714-1800 ?

See #230