Remove test case builder from generated incremental compilation tests

We currently use a builder for test cases in our generated tests for incremental compilation [1]. This needs to be replaced, because it makes debugging test failures very hard.

[1] https://github.com/kiegroup/drools/blob/f7ab4ee3c88d767a8cbb372c2db1afa84b20a51d/drools-compiler/src/test/java/org/drools/compiler/integrationtests/incrementalcompilation/AddRemoveTestBuilder.java