Fix build and test execution for legacy Java code

[rgorosito]

• Update ant source/target from 1.5 to 1.8
• Explicitly use org.safehaus.penrose.module.Module to fix compilation errors with newer JDKs
• Fix missing common/target classpath for samples
• Replace ${product.specification} with 2.0 in all .xml configuration files
• Disable forking in core tests to prevent JVM crashes

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PR created automatically by Jules for task 8417337492995408111 started by @rgorosito

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