Support differential fuzzing between Eclair and Lightning-kmp

[erickcestari]

Currently, we cannot run fuzzing with Eclair and LightningKMP simultaneously because only one JVM can be instantiated per process, so we must either find a way to run both in a single JVM without package conflicts, run them in separate processes, or accept that differential fuzzing between them is not possible or may find another solution for this.

cc @GustavoStingelin