The same speculative fix as in #5217.
The current working directory "." should have no reason to be in the
classpath if it is not equal to "$this_dir", hence it is removed.
The java-example project does not pull in any external dependencies, but
rather consists of three basic Java fuzzers that hit a synthetic bug
after a few seconds. The project can be used to verify that ClusterFuzz
correctly handles JVM fuzz targets.
* ExampleFuzzer fails with an assertion.
* ExampleValueProfileFuzzer fails with an exception after a few seconds,
but only if running in value profile mode.
* ExampleFuzzerNative fails with an ASan report.