Remove old scripts for parallel nesting examples

These scripts were providing handcrafted javac and java commands for compiling and running the parallel nesting examples. This becomes stale as the JVSTM version evolves and the scripts would have to be changed every time. A better way would be to embed them in the Maven POM, but that's too much work for such a simple thing (overkill imo). Hence why they're gone in this PR.